When an incoming call is sent to a SIP URI containing only numbers, or a combination of numbers and characters, the call fails. However, if the URI contains only alphabetic characters, the call succeeds. For example: • sip:number-4165551234@sip.vapi.ai results in a failed call, even though no credentials are configured. The system responds with: X-Reason: Invalid credentials • sip:number@sip.vapi.ai works without any issues, despite the same lack of credentials. This suggests that the presence of numeric characters in the URI may be triggering credential checks or authentication requirements.

Hi, could you please provide a call id where you experienced this issue? We would like to review the logs to identify the cause.

The issue is that they don't hit the system for some reason. I just get a 403 invalid credentials returned back in the SIP message.

If you are using the API to initiate calls, could you send the request payload you are using?

I'm not using the API, I'm setting calls to your SIP endpoint.