Hi Vapi Support Team, I'm experiencing an issue with my Telnyx–Vapi integration. The application works perfectly when tested directly from your web interface (the assistant responds and audio is transmitted correctly). However, when I call my Telnyx number connected to the same Vapi application, there is no audio on either side — I can’t hear the assistant, and the assistant doesn’t seem to receive my voice. In the Vapi call logs, the event shows: “silenced timeout”. Here are the details: Telnyx number: +34 (881) 17 08 29 Vapi application ID: 137e27b1-348b-4eda-82ce-36d181ccc8cd Call ID (example):019a22c6-db7a-766e-b8b1-33a1617595fb Timestamp of the call: 27 oct 2025, 00:07 The Telnyx app is already linked under “SIP Connection/Application” (not “Forward Only”). Everything appears to be configured correctly, so it seems to be an issue with audio streaming or media connection between Telnyx and Vapi. Could you please review this and let me know what might be causing the “silenced timeout” error? Thank you for your help,

Suggestion: Double-check your Telnyx SIP trunk configuration in Vapi to ensure your Telnyx number is correctly associated with the SIP trunk and that the assistant is assigned for both inbound and outbound calls. Here’s a quick example of the key step:

bash
curl -X POST https://api.vapi.ai/phone-number \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_VAPI_PRIVATE_KEY" \
  -d '{
    "provider": "byo-phone-number",
    "name": "Telnyx SIP Number",
    "number": "YOUR_PHONE_NUMBER",
    "credentialId": "YOUR_CREDENTIAL_ID"
  }'

Review the full [Telnyx SIP integration guide](https://docs.vapi.ai/advanced/sip/telnyx) and confirm all routing and assistant assignments are set as described. Source: - [Telnyx SIP integration](https://docs.vapi.ai/advanced/sip/telnyx)