> ## Documentation Index
> Fetch the complete documentation index at: https://www.sip.tg/llms.txt
> Use this file to discover all available pages before exploring further.

# Troubleshooting

export const subsc_opts = {
  all_workers: "Paid Workers",
  api_access: "API Access",
  call_duration: "Call duration",
  fail_calls: "Fail calls",
  group_size: "Group size",
  gw_sessions: "Additional sessions",
  lines: "Lines for Gateway",
  no_advert: "Disable notification",
  other_users: "Assign SIP accounts",
  parallel_call: "Call switching",
  phones: "Phones",
  recorder_allowed: "Call recording",
  recorder_call_duration: "Recording duration",
  sip_accounts: "SIP accounts",
  success_calls: "Success calls",
  sum_duration: "Total duration",
  tariff_activation: "Activation",
  template_owner: "SIP template owner",
  usage: "Usage"
};

export const bot = {
  ACTIVATE_TARIFF_PLAN: "Activate subscription",
  ADDRESS: "Address",
  ADDRESS_PORT: "Address:port",
  ADMIN_ASSIGN: "Assign administrator",
  APPLY: "Apply",
  ARBITRARY_CHECK: "Messages processing",
  AUTORENEW: "Auto renewal",
  AUTOREPLY: "Autoreply",
  BACK: "Back",
  BACK_TO_PAYMENT: "Back to payment",
  BALANCE_TRANSFER: "Transfer",
  BILLING: "Billing",
  BTN_CHARGE_REDIRECT: "Confirm charge",
  BTN_EMPTY_BOT: "Inline bot",
  BTN_TARIFF_NEW: "Activate",
  CALLBACK_CHECK: "Callback",
  CALLBACK_SWITCH_OFF: "Switch off Callback mode",
  CALLBACK_SWITCH_ON: "Switch on Callback mode",
  CALLER_NAME: "Caller name",
  CALLER_PHONE: "Caller phone",
  CANCEL: "Cancel",
  COMMENT: "Comment",
  CONFIGURE_ACCOUNT_ALLOW_EVERYBODY: "Allow calls from all users",
  CONFIGURE_ACCOUNT_ALLOW_P2P: "Allow P2P calls from everybody",
  CONFIGURE_ACCOUNT_DISALLOW_GROUPS: "Disallow adding to groups",
  CONFIGURE_ACCOUNT_OFF_OTHER_SESSIONS_CALLS: "Disable calls on other devices",
  COUNTRY: "Country",
  DELETE: "Delete",
  DESCRIPTION: "Description",
  DIAL_RULES: "Dial Rules",
  DOC_BTN_PROVIDE: "Provide documentation",
  DOMAIN: "Domain",
  DTMF_METHODS: "DTMF Methods",
  FIELD_VALUE: "Field:Value",
  FORMATS: "Audio Codecs",
  FW_ADD: "Add phone number",
  FW_ADD_OTHER: "Other number",
  FW_ADD_SELF: "Telegram number",
  FW_ANTISPAM: "Anti-spam",
  FW_BACK: "Back",
  FW_BONUS_PROGRAM: "Referral program",
  FW_CANCEL: "Cancel",
  FW_DELETE: "Delete",
  FW_NAME: "Name",
  FW_NO: "No",
  FW_PHONE_FORWARDING: "Remind number",
  FW_RECORDER_CHAT: "Chat for recordings",
  FW_RECORDER_CHECKBOX: "Call recording",
  FW_SELECT_COUNTRY: "Choose country (region)",
  FW_SHARE_PHONE: "Send phone number",
  FW_TELL_FRIENDS: "Tell friends",
  FW_YES: "Yes",
  GATEWAY_IN_RESET: "Reset Password",
  GATEWAY_IN_SHOW: "Show Account",
  GATEWAY_OUT_NUMBER: "Number on PBX",
  GENERATE_NEW: "Generate new",
  GIVE_ACCESS: "Give the access",
  GIVE_PHONE_NUMBER: "Give phone number",
  HELP: "Help",
  INLINE_QUERY: "Inline query",
  INVOICE_BANK_IGNORE_CURRENT_RATE: "Ignore currency rate",
  KEYPAD_IN: "DTMF In",
  KEYPAD_OUT: "DTMF Out",
  KEYS_GET: "Get Keys",
  KEYS_RESET: "Reset Keys",
  LEARN_ABOUT: "Learn about SIP.TG",
  LINES: "Lines",
  LINES_CHECK: "Lines",
  LOGIN: "Login",
  MANUAL: "Manual",
  MODE_GATEWAY: "Gateway mode",
  MODE_SOFTPHONE: "Softphone mode",
  NAME: "Name",
  NEW: "New",
  NEW_IN: "🆕 PBX→SIP․TG",
  NEW_IP: "🆕 IP⇿IP",
  NEW_OUT: "🆕 SIP․TG→PBX",
  NO: "No",
  PARALLEL_DECLINE: "Decline",
  PARALLEL_END: "End",
  PARALLEL_SWITCH: "Switch",
  PARALLEL_TRANSFER: "Transfer",
  PASSWORD: "Password",
  PAYER: "Payer",
  PAYSYSTEM_BTN_VERIFY: "Specify country of residence",
  PAYSYSTEM_DOCS_PROVIDE: "Provide documents",
  PAYSYSTEM_METHOD: "Payment method",
  PAY_TARIFF: "Pay",
  PROLONG: "Renew",
  PROMO_BUTTON_EMPTY: "Discount code",
  RECONNECT: "🔄 Reconnect",
  RECORDER_ACTIVATE: "🔴 Start recording",
  RECORDER_ACTIVATE_FAILED: "⚠️ Start recording",
  RECORDER_CHAT: "Chat for recordings",
  RECORDER_CHECKBOX: "Call recording",
  RECORDER_DEACTIVATE: "🟥 Stop recording",
  RECORDER_DEACTIVATE_RECONNECTING: "⌛ Stop recording",
  RECORDER_LOCKED: "🔒 Recording locked",
  REDIAL: "Redial",
  REDIAL_CHECK: "Redial",
  REGISTRAR: "Proxy",
  REPEAT: "Repeat",
  SELECT_BOT: "Select bot",
  SELECT_CHANNEL: "Select channel",
  SELECT_CHAT: "Select chat",
  SELECT_USER: "Select user",
  SERVER_FROM_TEMPLATE: "Settings templates",
  SESSION_BILLER_CHECK: "Use a shared subscription",
  SESSION_CONFIGURE_ACCOUNT: "Configure Telegram account",
  SESSION_LOGIN: "Connect",
  SESSION_LOGOUT: "Disconnect",
  SETTINGS: "Settings",
  START_CALLING: "Go to calls",
  SUPPORT: "Support",
  SWITCH_OFF: "Switch off",
  SWITCH_ON: "Switch on",
  TAKE: "Take",
  TARIFF_ACTIVATE_CHANGE_USER: "Change customer",
  TARIFF_ACTIVATE_USER: "Activate for customer",
  TARIFF_ACTIVATE_YOURSELF: "Activate yourself",
  TAX_ADDRESS: "Address",
  TAX_BUSINESS: "Business",
  TAX_NAME: "Buyer",
  TAX_NUMBER: "Tax number",
  TERMINATE_SESSION: "Terminate the session",
  TERMS_AGREE: "Agree with Terms and Conditions",
  TG_STORAGE_OFFICIAL: "✅ SIP․TG Sessions Storage",
  TRANSFER: "Transfer",
  TRANSFER_BACK: "Transfer back",
  TRUSTED_IPS: "Trusted IPs",
  UNLINK: "Unlink",
  USER: "User",
  VERIFY_ROUTE_BAD: "👎 No, it's spam",
  VERIFY_ROUTE_GOOD: "👍 Yes, all good",
  VERIFY_ROUTE_RECOVER: "Recover incoming calls",
  WORKER_AUTO: "Auto",
  YES: "Yes"
};

Below are possible errors that may occur when using the **Gateway** (PBX→Telegram mode) — both during registration (PBX→SIP.TG) and at the moment of call establishment (SIP→Telegram or Telegram→SIP). Some of them appear in PBX logs, some — as a displayed code when trying to call a Telegram account. Not all errors are frequently encountered in real operation, but it's useful to know about them for diagnostic purposes.

For reference:

* **Manager** — the controlling component of SIP.TG, responsible for connecting to Worker servers and Session Storages.
* **Worker** — the working component that processes calls, RTP traffic, and performs SIP signaling.

If you're just getting started with the Gateway, we also recommend checking out these articles:

* [Interaction with Telegram](/en/docs/gateway/telegram) — how to authorize a Telegram account for calls.
* [Interaction with PBX](/en/docs/gateway/pbx) — detailed description of SIP connection options.
* [Subscriptions Overview](/en/docs/subscriptions/pricing) — to ensure your "Gateway" subscription covers the required number of lines.

<a id="faq" />

## Frequently Asked Questions

<AccordionGroup>
  <Accordion title="What happens if someone calls this account directly?">
    When setting up the Gateway, the Telegram account forwards incoming calls to the PBX.\
    If a person is on the list of allowed callers, the call will be directed to the PBX, and on the device where this account is open, you can also manually answer the call.\
    It's usually recommended to disable call reception on other devices so that everything goes through the PBX.
  </Accordion>

  <Accordion title="Can I work with multiple Telegram accounts at once?">
    Yes, in the "Gateway" subscription, you can pay for multiple Telegram accounts. The first account costs 15 EUR/month, each additional one costs 150 EUR/month.
  </Accordion>

  <Accordion title="What if I need to process text messages too?">
    The Gateway can process incoming messages if you enable the **{bot.ARBITRARY_CHECK}** option in the gateway settings. This enables auto-reply, Callback mode, and message processing by an external bot.\
    For more details, see [SIP.TG Session Settings](/en/docs/gateway/telegram#session-settings).
  </Accordion>

  <Accordion title={`How to disable any messages during and after a call (DTMF keys, ${bot.REDIAL}, etc.)?`}>
    In your Telegram session settings, disable the following options: **{bot.KEYPAD_IN}**, **{bot.KEYPAD_OUT}**, **{bot.REDIAL_CHECK}**, **{bot.LINES_CHECK}** and **{bot.ARBITRARY_CHECK}**.
    For more details, see [SIP.TG Session Settings](/en/docs/gateway/telegram#session-settings).
  </Accordion>

  <Accordion title="How reliable is this?">
    The entire SIP.TG infrastructure is distributed across multiple data centers. Nevertheless, for mission-critical systems, you might consider your own Worker servers.
  </Accordion>

  <Accordion title="Which Telegram account is best to use as a Gateway?">
    It's recommended to create a separate work account for the company — so that your personal Telegram doesn't mix with business calls. It's important that this account is always online (or store the session in the SIP.TG Cloud Storage).
  </Accordion>

  <Accordion title="Can I do cold calling via the gateway Telegram account? Won't it be blocked?">
    Telegram may limit or completely block your gateway Telegram account. We do not recommend this activity and we do not transfer a subscription to another Telegram account in case of blocking.

    However, if you want to preserve the subscription, we have a solution:

    1. Activate the "Gateway" subscription for an Administrator (see [Roles of session and administrator accounts](/en/docs/gateway/telegram)) with the option **{subsc_opts.gw_sessions}** ≥ 1.
    2. From the administrator, create a new Telegram session linked to the account used for calls.
    3. Enable the **{bot.SESSION_BILLER_CHECK}** option for the created session.
    4. If the calling Telegram account gets blocked, Disconnect the session via the session settings in the `/gateway` section **while keeping the current settings**, and Connect a new Telegram account there.
  </Accordion>

  <Accordion title="Can one Telegram account be shared among multiple employees?">
    Yes, but this means that everyone will be using the same Telegram account, and incoming calls will come to all devices simultaneously. As soon as one person answers, the call will be dropped for the others.
  </Accordion>

  <Accordion title="Why is the call dropped for others when one person answers?">
    This is normal Gateway behavior: the PBX sees that the call has already been accepted. A CANCEL is sent to other clients. If you want each employee to have their own Telegram account, use multiple gateway subscriptions.
  </Accordion>

  <Accordion title="Is a SIM card required?">
    A Telegram account is created based on a phone number. Usually, you take any SIM card, register it with Telegram, and then the number may not be used for traditional operator voice calls. The main thing is not to lose access to this number for Telegram recovery.
  </Accordion>

  <Accordion title="What is the port range used for RTP?">
    Our SIP stack is based on Yate, where the default UDP port range is 16384-32768.
  </Accordion>
</AccordionGroup>

<a id="general" />

## General Issues

<AccordionGroup>
  <Accordion title="Incoming call not reaching the Telegram gateway">
    * Check that the Telegram account is active and not blocked by the messenger.
    * Make sure that in Telegram privacy settings, calls from everyone are allowed.
  </Accordion>

  <Accordion title="One-way audio when using the Gateway">
    As with the Softphone, this is most often a question of codecs or network restrictions.

    * Try specifying a specific codec (`alaw` or `mulaw`).
    * Make sure that UDP traffic is allowed.
  </Accordion>

  <Accordion title="DTMF not recognized in voice menu">
    * Make sure that in the SIP account settings (Gateway), the method RFC2833 or INFO is selected, compatible with your PBX.
    * Try switching the codec, sometimes inband DTMF and high compression don't work well together.
  </Accordion>
</AccordionGroup>

<a id="sip" />

## Common SIP Errors

Such responses may appear both during calls and during simple SIP trunk registration. The code below is sent by the SIP.TG server to your PBX.

<AccordionGroup>
  <Accordion title="401 Unauthorized">
    **Essence:** Standard response when using SIP Digest Auth. The PBX sends an INVITE or REGISTER without a complete set of authorization data, and the SIP.TG server requests authorization.\
    If error 401 appears repeatedly many times in a row, it means that either the password/login is incorrect, or Digest Auth support is disabled on the PBX side.

    **What to do:**

    * Make sure that the login/password from [@siptg\_bot](https://t.me/siptg_bot?start=utm_docs) (section `/gateway`) is correctly entered in your PBX settings.
    * Check that SIP authorization mode (Digest Auth) is enabled in the PBX itself.
    * If necessary, change the password in `/gateway` and enter it again.
  </Accordion>

  <Accordion title="402 …">
    **Essence:** "Gateway" subscription limitation. This means that the Telegram account has no paid lines for Gateway mode, the subscription has expired, or the resource volume is exceeded.

    **What to do:**

    * In the [@siptg\_bot](https://t.me/siptg_bot?start=utm_docs) with the command `/subscriptions`, check if the "Gateway" plan is active and if there are enough lines.
    * If the subscription period has expired or additional lines are needed, arrange for renewal / extension of the subscription (see [Subscription Overview](/en/docs/subscriptions/pricing)).
    * Make sure that the specific Telegram account is actually linked to the right subscription (when paying for multiple accounts).
  </Accordion>

  <Accordion title="500 Database error">
    **Essence:** Internal error on the SIP.TG side related to the database. Such cases are extremely rare.

    **What to do:**

    * Usually temporary in nature and is automatically resolved.
    * Try again, if the error occurs regularly, seek help. For more details, see [How to Get Help](/en/docs#help).
  </Accordion>

  <Accordion title="503 No response from Manager">
    **Essence:** The Worker cannot connect to the SIP.TG Manager server due to an internal network problem. Your PBX will see this as a `503 No response from Manager` response.

    **What to do:**

    * As a rule, these are short-term failures. Try waiting 1-2 minutes and repeat the call.
    * If the problem persists, you can switch the SIP trunk to another Worker server (see [Interaction with PBX](/en/docs/gateway/pbx)).
  </Accordion>
</AccordionGroup>

<a id="register" />

## Errors during PBX → SIP.TG registration

Here are responses that may come when your PBX tries to register with the SIP.TG Worker server (connection with the PBX→SIP.TG type). All errors listed below usually have code 403 or 404.

<AccordionGroup>
  <Accordion title="403 Wrong password">
    **Essence:** The PBX correctly tries to authenticate, but the specified password does not match what SIP.TG expects.

    **What to do:**

    * Check the password in the `/gateway` section of [@siptg\_bot](https://t.me/siptg_bot?start=utm_docs) and compare with what is entered on the PBX.
    * If necessary, change the password in the bot (the "Change password" button) and enter the new one on the PBX side.
    * Make sure that the login (username) also does not contain typos.
  </Accordion>

  <Accordion title="403 Untrusted IP address">
    **Essence:** The password is correct, but your IP address is not in the list of allowed addresses for this SIP connection.

    **What to do:**

    * In [@siptg\_bot](https://t.me/siptg_bot?start=utm_docs), section `/gateway`, open the settings of the corresponding SIP connection and:
      * Add your IP address to the trusted list.
      * Or clear the list to allow connections from any IP (but observe security measures).
    * If your external IP changes in your network, take this into account when configuring (perhaps it's worth completely disabling ACL).
  </Accordion>

  <Accordion title="403 Telegram session is inactive">
    **Essence:** The Telegram account to which the binding is going is inactive (authorization has been lost). As a result, SIP.TG refuses to register the trunk, as there is no real Telegram connection.

    **What to do:**

    * In [@siptg\_bot](https://t.me/siptg_bot?start=utm_docs) in the `/gateway` section, reconnect the Telegram account (authorize the phone number).
    * If the Telegram account has been deleted, you will have to assign another phone number for the Gateway.
    * For more details, see [Interaction with Telegram](/en/docs/gateway/telegram).
  </Accordion>

  <Accordion title="403 Session storage is inactive">
    **Essence:** The storage where the Telegram session is saved (cloud or your own Sessions storage) is currently turned off or unavailable. Consequently, there is no possibility to work with the Telegram session.

    **What to do:**

    * If you use the SIP.TG cloud storage, check the status in `/gateway`. Usually such failures are short-lived.
    * If you have your own Session Storage, make sure it is running and available. If necessary, switch to the SIP.TG cloud.
  </Accordion>

  <Accordion title="403 Worker is inactive">
    **Essence:** The selected Worker server is disabled on the SIP.TG side or is in the process of updating/restarting. The server cannot accept PBX→SIP.TG registration.

    **What to do:**

    * In the bot's `/gateway` section, check the Worker settings. If the server is disabled, select another one or wait until it becomes active again.
    * If this is your [own Worker](/en/docs/additional/modules#worker), start/restart it.
  </Accordion>

  <Accordion title="403 Worker address is not set">
    **Essence:** The Worker server configuration does not provide for connections with the "PBX→SIP.TG" type. For example, the server is only configured for "SIP.TG→PBX" or "IP⇿IP".

    **What to do:**

    * In [@siptg\_bot](https://t.me/siptg_bot?start=utm_docs), double-check the connection type (PBX→SIP.TG) and select an appropriate Worker.
    * Create another type of SIP connection ("SIP.TG→PBX" or "IP⇿IP").
  </Accordion>

  <Accordion title="403 Route is not permitted">
    **Essence:** Access to the used Telegram session has been revoked or no longer belongs to you. For example, the administrator who created the session has been deprived of rights, and you cannot use this session.

    **What to do:**

    * Create your own Gateway session. In the bot's `/gateway` section, connect the Telegram number that you control.
    * Make sure that the administrator who previously created the session did not take away your access.
  </Accordion>

  <Accordion title="404 Route not found">
    **Essence:** The login specified in the SIP request does not exist or has already been deleted. The SIP.TG server does not find such an "account".

    **What to do:**

    * Double-check the login/username that you received in the `/gateway` section.
    * If this record was previously deleted, create a new one.
    * Make sure that your PBX has exactly the login that was issued by the bot (without extra characters or spaces).
  </Accordion>
</AccordionGroup>

<a id="sip-tg" />

## Errors when calling SIP → Telegram

These errors occur when your PBX is already registered (or IP-to-IP), and during an outgoing call to Telegram, the SIP.TG server returns a code if it cannot correctly call the Telegram account.

<AccordionGroup>
  <Accordion title="403 USER_PRIVACY_RESTRICTED / 403 PRIVACY_PREMIUM_REQUIRED">
    **Essence:** The Telegram user has restricted the circle of people who can call them (e.g., only contacts or users with premium subscription), and your gateway account is not on this list.

    **What to do:**

    * Ask the called user to configure call permission: "Settings → Privacy → Voice Calls" → "All users" or add your gateway account to "Always allow".
    * Or use an account that is actually in the target user's contacts.
  </Accordion>

  <Accordion title="404 Not Found / 404 Chat not found / 404 USERNAME_NOT_OCCUPIED">
    **Essence:** SIP.TG could not find the Telegram account by the transmitted identifier (number, user\_id, username). Telegram may return such a response if:

    * The number is indeed not registered in Telegram.
    * The username does not exist or has been released.
    * The profile is unavailable due to restrictions.
    * Your gateway account searches for a phone number too frequently.

    **What to do:**

    * Make sure you are using the correct identifier (if using a phone — it should be a real Telegram number).
    * If it happens often, check if you made a mistake in the format. It might be better to use the internal user\_id.
  </Accordion>

  <Accordion title="405 REGISTER is required first">
    **Essence:** You are sending an INVITE without a prior PBX→SIP.TG registration, while the Worker requires a full REGISTER.

    **What to do:**

    * Enable "Registration" mode on your PBX side (register the PBX→SIP.TG trunk). For more details, see [Interaction with PBX](/en/docs/gateway/pbx).
  </Accordion>

  <Accordion title="408 Timeout of waiting RPC result">
    **Essence:** The Telegram server did not respond in time, or the SIP.TG request hung when accessing Telegram. This happens during overload or Telegram anti-spam filter, when there are many outgoing calls in a short time.

    **What to do:**

    * Reduce the intensity of outgoing calls.
    * Wait and try again if it was a temporary failure.
  </Accordion>

  <Accordion title="470 Anonymous user">
    **Essence:** SIP.TG is trying to call a user by their internal user\_id, with which there is no explicit confirmed contact. Telegram rejects such "anonymous" calls.

    **What to do:**

    * Usually you need to either call by a confirmed number or username, or have the user add you to contacts or write to you first.
  </Accordion>

  <Accordion title="500 (others)">
    **Essence:** Any other internal error on the Telegram side. Sometimes this designates unexpected failures during audio channel processing, internal overload, etc.

    **What to do:**

    * Check the stability of the network, repeat the call.
    * If the error appears regularly on the same number, seek help. For more details, see [How to Get Help](/en/docs#help).
  </Accordion>

  <Accordion title="503 Account is not running">
    **Essence:** The SIP.TG Worker server received an INVITE, but there is no active session for the needed account. That is, the PBX could have sent an INVITE without waiting for a response to REGISTER.

    **What to do:**

    * Make sure that the PBX→SIP.TG trunk is successfully registered and the Worker sees an active account.
    * Sometimes it helps to restart the trunk on the PBX. If necessary, see [Interaction with PBX](/en/docs/gateway/pbx).
  </Accordion>

  <Accordion title="503 Session is not running">
    **Essence:** The Telegram session is actually disconnected. It's possible that in the [@siptg\_bot](https://t.me/siptg_bot?start=utm_docs), the session is displayed, but it's not actually authorized.

    **What to do:**

    * Double-check the session status in `/gateway`, if necessary, re-authorize the Telegram number.
    * If the error occurs frequently, try switching to another Worker or restarting the account.
  </Accordion>

  <Accordion title="503 Telegram storage is unavailable">
    **Essence:** SIP.TG has lost connection with the Telegram session storage, so it cannot find out the current status or create a call.

    **What to do:**

    * If you use cloud storage, wait for recovery (usually a minute or two).
    * If your own Session Storage, check the logs and status of the module.
  </Accordion>

  <Accordion title="503 Too Many Requests: retry after … / 503 PEER_FLOOD">
    **Essence:** This is Telegram's anti-spam protection, when too many outgoing calls occur in a short period, especially to unfamiliar numbers.

    **What to do:**

    * Reduce the dialing speed (on the PBX side or your script).
    * Use several different Telegram accounts to distribute the load.
    * Wait for the specified time "retry after N", then try again.
  </Accordion>

  <Accordion title="503 Worker is not ready">
    **Essence:** The Worker was recently restarted or is being updated, and has not yet completed initialization. As a result, calls are rejected at the SIP level.

    **What to do:**

    * Wait 1-2 minutes and try the call again.
    * Or in [@siptg\_bot](https://t.me/siptg_bot?start=utm_docs), select another Worker server for your connection.
  </Accordion>
</AccordionGroup>

<a id="tg-sip" />

## Errors when calling Telegram → SIP

Here we consider situations when a real user tries to call the Gateway account from the Telegram application, and the Worker tries to transfer the call to your PBX. If the PBX returns an error, or if an error occurs on the SIP.TG side, the user may see an error in the chat with the Gateway account.

In this section, we only list those errors that may occur on the SIP.TG side.

<AccordionGroup>
  <Accordion title="482 Caller has active gateway accounts">
    **Essence:** The SIP.TG Gateway is also activated on the caller's account. The service blocks such an attempt (Telegram→SIP) to prevent looping or unforeseen call loops.

    **What to do:**

    * If you really need to receive calls from an account that is also a gateway, it's better to use a different mode for it (e.g., [Softphone](/en/docs/softphone)) or another Telegram account without Gateway.
  </Accordion>

  <Accordion title="503 SIP account is unavailable">
    **Essence:** During an incoming call from Telegram, the Worker could not reach your PBX. This can happen if the PBX→SIP.TG trunk is down, or if you have IP-to-IP, but the required port is not responding.

    **What to do:**

    * Make sure that the PBX is registered (with PBX→SIP.TG) or that the IP-to-IP connection is active.
    * Check that SIP/UDP packets are not blocked in your firewall, and that you have opened RTP ports.
    * For more details, see [Interaction with PBX](/en/docs/gateway/pbx).
  </Accordion>

  <Accordion title="503 Worker is unavailable">
    **Essence:** The Worker server is currently unavailable for call transfer (network problems or restart), and the call is rejected with code 503.

    **What to do:**

    * Wait for some time or switch the Gateway account to another Worker (the bot's `/gateway` section).
    * If it's your own Worker server, check its logs and restart if necessary.
  </Accordion>
</AccordionGroup>

<Info>
  If none of the listed solutions helps, seek assistance. For more details, see [How to Get Help](/en/docs#help).
</Info>
