### Answer The "international numbers not supported" error applies specifically to numbers purchased directly from Retell. [(1) ]() For numbers bought through Retell, outbound international calling has limitations. The

outbound_allowed_countries

setting controls which countries your phone number can call, but this setting works with custom/imported numbers via SIP trunk. [(2) ]() Your options: 1. Use a custom SIP trunk setup - Import your number via Twilio or Telnyx elastic SIP trunk instead of using a Retell-purchased number. This allows international dialing. [(3) ]() 2. For Twilio SIP trunk international dialing - Search "geo" in Twilio to find the "Voice Geographic Permissions" setting and enable the countries you need. You can configure allowed outbound countries via API like this:

curl -X PATCH "<https://api.retellai.com/update-phone-number/+14155551234%22> \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "allowed_outbound_country_list": ["US", "CA", "NL"]
  }'

[(2) ]() However, for Retell-purchased US numbers, international outbound may not be supported regardless of this setting. Consider importing a number from Twilio/Telnyx via SIP trunk for full international calling capability. [(1) ]() , [(3) ]()

​ To learn more, see the sources I considered: [[1] Error in Number Formatting](https://discord.com/channels/1186424376300679209/1344337067051716619) [[2] Fraud Protection](https://docs.retellai.com/reliability/fraud-protection) [[3] I’m trying to use a toll-free number (connected from Twilio through a SIP trunk)](https://retell.discourse.group/t/i-m-trying-to-use-a-toll-free-number-connected-from-twilio-through-a-sip-trunk/127) ​

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