The "call.start.error-get-transport" indicates an issue retrieving transport information when initiating the call, which prevents the call from reaching Twilio. Here are some steps to help resolve this: 1. Recheck Twilio Configuration: Ensure that the Twilio Account SID and Auth Token are correct and re-save them in the Vapi dashboard. Ensure the Twilio account is active, has sufficient credit, and that the number is voice-enabled. 2. Vapi Number Configuration: Verify that the imported Twilio number is properly configured in Vapi. Use the

/phone-numbers

endpoint to ensure the number details are correctly registered. 3. Outbound Call Setup: Ensure that the configured Twilio number allows outbound calls to the destination (Slovenia). Check the geographic permissions in the Twilio console. 4. Transport Settings: Although you mentioned no transport overrides, ensure that the transport settings align with the intended setup. Consider including transport details in the payload: 4.

"transport": {
  "provider": "twilio",
  "audioFormat": {
    "format": "pcm_s16le",
    "container": "raw",
    "sampleRate": 16000
  }
}

5. Review Vapi Logs: Check the Vapi call logs for any additional error details that might indicate why the transport lookup is failing. Access the [call logs](https://dashboard.vapi.ai/calls) for more information. 6. API Key Validation: Ensure the Vapi API key used in your requests is valid and has the necessary permissions. For more in-depth analysis, verify each configuration step matches the expected setup and correct any discrepancies found.