Retell phone number: +447427914908 (shown as +44 7427 914908 in UI) Provider: Custom telephony Inbound Call Agent assigned: Conversation Flow Agent 2 / V13 Agent ID used in Twilio origination URI: agent_12313fb9b5d7d67639bf164541 (confirmed matches agent) Twilio Elastic SIP Trunk: TKd56b90319f07c6d54d17d5a3b9c9dcf1 (US1) Example Twilio Call SID: CAfa82347a6ccc918a00f50c2691decdb8 Twilio shows: Direction Trunking Originating, Type sip-pstn, Status No Answer, Duration 0s Retell Call History shows no custom_telephony calls created (only web_call) SIP PCAP not available (need guidance where to enable / whether you can provide server-side logs) Question: Can you check on your side why INVITEs to sip:agent_123...@sip.retellai.com;transport=tls are not creating a call session? Is there an account/verification/telephony enablement gate, or a region mismatch (Twilio US1) preventing inbound SIP acceptance?

You’re using the wrong format, you cant use sip:agentid

what should it be replaced with?

Follow our sip trunking guide, if using twilio it should just be sip:sip.retellai.com

I keep getting the message, 'the person you're calling is on another call' Twilio Call SID: CA5200849e77a375c80781516cd6ee725c Twilio Trunk SID: TKd56b90319f07c6d54d17d5a3b9c9dcf1 Called number (DID): +447427914908 Origination URI: sip:sip.retellai.com Retell Phone Number entry: Luvio Line (Provider: Custom telephony) What happens: Caller hears “they’re on another call”, Twilio status shows Busy/Failed, duration 0s, no session appears in Retell Call History Attached: Twilio SIP PCAP from the call https://cdn.discordapp.com/attachments/1477447459184578571/1478023249794175110/call-log-CA5200849e77a375c80781516cd6ee725c.pcap?ex=69c2936b&is=69c141eb&hm=1fce2369004cc97fc667f3fb3b5f5a99b9a03752b5758381772119b415fcf622&

can you share screenshots of your current trunking settings, something must not be connected right

working now, thanks for your help