Hey I’m running into a couple of issues while setting up my Telnyx SIP number with Vapi, and I’d love your help! I added the number via the API following the Telnyx integration docs: 🔗 https://docs.vapi.ai/advanced/sip/telnyx#4-add-your-telnyx-sip-credentials-to-vapiai Everything looks good — the number appears in my dashboard and it's marked as active. Problem 1: When I try to select my assistant in the Outbound Settings, I can choose it in the dropdown, but the value doesn’t get saved. No error shows up — it just resets after selecting. I’ve tried multiple browsers, same result. Is this a known UI bug? Should I assign the assistant another way (e.g. API)? Problem 2: Possibly related — I can’t make outbound calls. The call attempt fails and I get this in the logs: An error occurred in this call: call.in-progress.error-sip-telephony-provider-failed-to-connect-call https://www.loom.com/share/25e585458d8c43cf9a3821442b2ba449?sid=f01219e4-16ec-40e4-b087-f10430edff76 Thx

Hey there! 👋 I wasn't able to find specific confirmation about the assistant selection not saving in Outbound Settings being a known bug. However, I can definitely help with both issues you're experiencing! ## Problem 1: Assistant Selection Not Saving While I don't have official confirmation about this specific UI issue, there have been similar reports of settings not saving in the Vapi UI. For example, users have reported issues with server URL secrets getting removed in assistant advanced settings and voice selections not saving in squads. As a workaround, you can assign an assistant to your Telnyx SIP number via the API using a PATCH request:

curl --location --request PATCH 'https://api.vapi.ai/phone-number/your_phone_id' \
--header 'Content-Type: application/json' \
--header 'Authorization: Bearer your-vapi-private-api-key' \
--data '{
"assistantId": "your-assistant-id"
}'

Just replace

your_phone_id

with the ID of your Telnyx SIP number and

your-assistant-id

with the ID of the assistant you want to assign. ## Problem 2: SIP Connection Error For the "call.in-progress.error-sip-telephony-provider-failed-to-connect-call" error, there are several potential causes: 1. **Telephony Provider Issues**: Telnyx might not be responding or connecting in the required time, leading to the connection failure. 2. **SIP Configuration Issues**: According to information from [Discord discussions](https://discord.com/channels/1211482211119796234/1340144301132353637), this could be related to problems with your SIP configuration. 3. **Network Configuration**: Make sure your network allows SIP traffic and that any firewalls aren't blocking it. Here are some troubleshooting steps: - Verify your SIP trunk is correctly configured in Vapi with the proper Credential ID, IP/Port, and authentication details - Ensure SIP Register is enabled with the correct Domain and Realm - Check that the SIP URI in your configuration is correctly formatted

Hey Row1, could you share a Loom video describing you could not save the assistant for the outbound phone call for your phone number? This will help us reproduce the error and then eventually get it fixed for you if possible. Along with it, also share the phone number ID. Coming to the second thing to find out why sip calls are not working resulting into error "fail to connect". Could you share the call ID so I can go through it and then look into the logs what might have been not working right for you?

@Rw1 Let me know how did you solve the problem and how SIP trunking is costing you per minute?

This ticket has been marked as solved, and as a result, you will no longer receive any further responses. Kindly create a new support ticket to escalate your inquiry.