### Answer The disconnection reason

telephony_provider_unavailable

indicates that the outbound call was not connected because the telephony provider (Twilio in your case) is unavailable. [(1) ]() What this means: According to the documentation,

telephony_provider_unavailable

with call status

not_connected

means "the telephony provider is offline or failing." , [(2) ]() Troubleshooting steps: 1. Verify Twilio account status – Check that your Twilio account is active and has sufficient balance for international calls to India. 2. Check Twilio geographic permissions – Ensure India (+91) is enabled in your Twilio account's geographic permissions for outbound calling. This is a common issue for international destinations. 3. Verify SIP trunk credentials – If you're using custom telephony/SIP trunking, ensure your credentials are properly authenticated. The related error

telephony_provider_permission_denied

indicates "the sip trunk credentials are not authenticated." [(1) ]() 4. Check Twilio service status – Verify there are no ongoing Twilio outages affecting calls to India. 5. Test the number directly in Twilio – Try making a test call to the same Indian number directly through Twilio's console to isolate whether the issue is with Twilio or the Retell integration. If all Twilio settings appear correct, you may want to reach out to Twilio support to verify international calling to India is fully enabled on your account.

​ To learn more, see the sources I considered: [[1] Debug call disconnection](https://docs.retellai.com/reliability/debug-call-disconnect) [[2] Chat Widget, Custom Function Enhancement and more!](https://www.retellai.com/changelog/chat-widget-custom-function-enhancement-and-more) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.