We’re setting up a new number, and outbound calls are working correctly, but inbound calls are failing with a 404 error. We’re using a SIP Trunking credential address (via integrations). Our SIP provider shared a test log file showing the error that occurs on their side when an inbound call is made. Outbound calls using the same number and SIP trunk configuration are working as expected. It appears the issue may be on VAPI’s side. Could you please help us investigate and resolve this? Please contact me or @Ade

Thank you for the details. To help investigate the inbound 404 error, could you confirm if your SIP provider is forwarding inbound calls to the correct SIP URI (e.g.,

sip:YOUR_NUMBER@sip.vapi.ai

) and that this number is registered and linked to a Vapi assistant in your dashboard? Sources: - [Twilio SIP Integration](https://docs.vapi.ai/advanced/sip/twilio) - [SIP Trunking](https://docs.vapi.ai/advanced/sip/sip-trunk)

Hi AJH, It looks like you're encountering SIP call errors. Here are some key points from our documentation to consider: 1. **SIP Error Codes**: New error codes like

call.in-progress.error-providerfault-outbound-sip-403-forbidden

and

call.in-progress.error-providerfault-outbound-sip-480-temporarily-unavailable

provide more specific insights into call failures. Make sure to update your error handling to account for these codes. You can find more details in the [SIP Call Error Handling Updates](https://docs.vapi.ai/changelog/2025/5/31). 2. **Inbound Call Failure Reasons**: Two new

endedReason

values have been added for better diagnosing SIP inbound call failures. These can help in identifying whether a caller hung up before the call connected or if there was a connection error. Check this update in the [New Ended Reasons for SIP Inbound Calls](https://docs.vapi.ai/changelog/2025/6/7). 3. **SIP Trunk Configuration**: Ensure that your network settings are correct, including allowlisting the necessary IP addresses, and that your SIP configuration is aligned with best practices. For setup specifics, refer to the [SIP Trunking documentation](https://docs.vapi.ai/advanced/sip/sip-trunk). These resources should help in troubleshooting and resolving your SIP call issues efficiently.

"Could you please run these two telnet tests from your side and let me know the results? I'm getting the exact same behavior." telnet 44.238.177.138 5060 (Should CONNECT ✅) telnet 44.229.228.186 5060 (Should FAIL or TIMEOUT ❌) "I need to confirm if the second IP is unreachable for you too, which would indicate a routing issue outside of my local network."

We’ll share an update as soon as we have more information. Thank you for bearing with us and for your patience while we work to get everything back to normal.