> For the complete documentation index, see [llms.txt](https://help.sipgate.de/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.sipgate.de/cloud-telefonanlage/en/using-sipgate/telefonie/was-bedeuten-die-telefonie-fehler-codes.md).

# What do the telephony & error codes mean?

#### The following error codes occur most frequently:

| **401** Incorrect credentials | The username (SIP ID) or password (SIP password) is incorrect.                                               |
| ----------------------------- | ------------------------------------------------------------------------------------------------------------ |
| **404** Unknown number        | The phone number does not exist, is not assigned to a line, or is not configured in the callee's device/PBX. |
| **486** Busy                  | The remote party reports that the subscriber is busy.                                                        |
| **487** Hung up               | The usual signal when the remote party hangs up.                                                             |

#### Other commonly transmitted codes:

| **100** Processing                    | An attempt is being made to connect the call. This code is part of the normal call setup process.                                    |
| ------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------ |
| **180** Ringing signal                | The ringing is signaled by the callee's device.                                                                                      |
| **183** Connection setup              | The connection is currently being established. You may hear a ringtone or an announcement.                                           |
| **200** OK                            | The call was accepted, or the device has registered with the server.                                                                 |
| **301** Permanently forwarded         | A permanent forwarding to another destination is set up.                                                                             |
| **302** Temporarily forwarded         | A temporary call forwarding is set up on the callee's phone.                                                                         |
| **400** Bad request                   | The request contains incorrect parameters. This usually means that you entered data into the wrong field in the phone configuration. |
| **403** Not allowed                   | The subscriber does not have permission to make this call.                                                                           |
| **407** Proxy authentication required | For outgoing calls, the phone must authenticate itself to the server.                                                                |
| **408** No response (Request Timeout) | Usually occurs when your router or firewall forwards data packets to the phone only partially or not at all.                         |
| **480** Temporarily unavailable       | This is received, for example, when the person being called has enabled DND/Do Not Disturb.                                          |
| **481** Call does not exist           | Rarely occurs, usually when a status message has not reached its destination.                                                        |
| **482** Loop routing detected         | Loop routing often created by forwarding (A ➔ B ➔ A).                                                                                |
| **488** Invalid call attempt          | Occurs when the codec used by the endpoint, the encryption, or the transmission method (e.g. video) is not supported.                |
| **500** Server error                  | General server error.                                                                                                                |
| **502** Wrong gateway                 | The gateway (server) in the SIP request is incorrect.                                                                                |
| **503** Service unavailable           | The server's SIP service is temporarily unavailable.                                                                                 |
| **603** Rejected                      | The remote party rejected the call. This can be done manually or automatically.                                                      |


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