> 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 login credentials | The username (SIP ID) or password (SIP password) is incorrect.                                                     |
| ----------------------------------- | ------------------------------------------------------------------------------------------------------------------ |
| **404** Unknown phone number        | The phone number does not exist, is not assigned to a line, or is not configured in the called party'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** Connecting                    | An attempt is being made to connect the call. This code is part of the normal call setup process.                                  |
| ------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------- |
| **180** Ringing                       | The ringing is signaled by the called party's device.                                                                              |
| **183** Call setup                    | The connection is being established. A ring tone or announcement may be heard.                                                     |
| **200** OK                            | The call was answered, 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 in the called party's phone.                                                                 |
| **400** Bad request                   | The request contains incorrect parameters. This usually means that you entered data in the wrong field of the phone configuration. |
| **403** Not allowed                   | The subscriber is not authorized to place 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 only partially or not at all to the phone.                       |
| **480** Temporarily unavailable       | You get this, for example, when the called party has activated DND/Do Not Disturb.                                                 |
| **481** Call does not exist           | Rarely happens, usually when a status message has not reached its destination.                                                     |
| **482** Loop routing detected         | Circular routing often created by forwarding (A ➔ B ➔ A).                                                                          |
| **488** Call attempt not allowed      | Occurs when the codec used by the device, the encryption or transmission method (e.g. video) is not supported.                     |
| **500** Server error                  | General server error.                                                                                                              |
| **502** Bad gateway                   | The gateway (server) in the SIP request is faulty.                                                                                 |
| **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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