Unable to add new phone number via SIP trunk (Internal Server Error)

Support Help
1

Hi,

I’m using Twilio Elastic SIP trunking with Retell custom telephony.

Existing number works:
+447427914908

New number attached to the same trunk:
+447476563455

When I try to add the new number in Retell → Phone Numbers I get:

Internal Server Error

Calls to the number reach sip.retellai.com but return “user busy”.

Could you check why the SIP number mapping cannot be created?

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Thanks

2

Twilio Call CAf7d5a157a12f4ea471cc1572c553cebb

3

Hello,

Kindly check our documentation on integrating custom telephony providers: https://docs.retellai.com/deploy/custom-telephony
We also have a specific guide on connecting Twilio account via SIP trunking: https://docs.retellai.com/deploy/twilio

Regards,
Omar Salam
Retell Support Team