We have multi-tenant sip servers and some of our customers are using VAPI. They are trying to make a call to your servers but receiving 491 Request Pending Signal. https://cdn.discordapp.com/attachments/1437683631593226240/1437683631920513105/image.png?ex=691422b8&is=6912d138&hm=d49a9071a701b8b1d5854228020d57632290e17a2927d4f197ca9cdfe3946802& https://cdn.discordapp.com/attachments/1437683631593226240/1437683632578891848/image.png?ex=691422b8&is=6912d138&hm=010bd503c00e9592654c03c9ea2c00495a6d2414d5ace74f32c6971a76a72375&

Suggestion: Double-check that all VAPI signaling IPs are whitelisted on your SIP server, as missing IPs can cause 401 Unauthorized and subsequent 491 Request Pending errors. For VAPI, ensure you have allowed the following IPs:

44.229.228.186/32
44.238.177.138/32

Update your firewall or SIP gateway configuration to include these IPs, then retest the call flow. For more details, see the [VAPI SIP trunking documentation](https://docs.vapi.ai/advanced/sip/sip-trunk). Source: - [SIP Trunking Vapi Documentation](https://docs.vapi.ai/advanced/sip/sip-trunk)

All of your IP adresses are in whitelist from our firewalls. We are still having this problem. Also, some of our customers are having problem about agents. Their calls are successfully connected to your server with 200 OK signal but there is some voicemail.

Hi SvollFarn, If you're encountering an error related to Tavus video processing, it might be linked to the

pipeline-error-tavus-video-failed

. This error was part of the improvements made on December 9, 2024, which include detailed error messages for better troubleshooting. Refer to the [changelog](https://docs.vapi.ai/changelog/2024/12/9) for more details on this update. For any specific scenarios like a 401 error or other validation failures, you can reference the relevant [API documentation](https://docs.vapi.ai/api-reference/webhooks/server-message) to understand the error messages. Let me know if you need further clarification on handling these errors.