Question
What do the various SIP response codes mean?
Applies To
- SIP
- Error Code
- Response Code
Answer
If your call returns any of the following SIP response codes, review the possible causes below:
| SIP Code | Meaning | Possible Cause |
|---|---|---|
| 400 | Bad Request | Invalid SIP request format. Check headers and syntax. |
| 401 | Unauthorized | Authentication credentials are missing or invalid. |
| 403 | Forbidden | Caller ID not allowed or call blocked by policy. |
| 407 | Proxy Authentication Required | The request must be authenticated by the SIP proxy. |
| 404 | Not Found | The number does not exist on the destination network. |
| 408 | Request Timeout | No response from the destination endpoint. |
| 480 | Temporarily Unavailable | Handset switched off, out of coverage, or VoIP client not registered. |
| 486 | Busy Here | The destination handset is busy or rejecting the call. |
| 487 | Request Terminated | Call cancelled by the user before completion. |
See RFC 3261 for complete documentation of standard SIP response codes, which the Vonage APIs comply with. If you are setting the eventUrl parameter in your Voice API request, or configure the callback URL for your virtual number for inbound calls, we will return the final SIP response of the call to your webhook.
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