Hi, I need help with inbound calls on Custom SIP trunking (LiveKit). My setup: Self-hosted Kamailio SBC → my carrier (Etisalat, UAE). My outbound works perfectly (Retell → my SBC → carrier → supplier). I'm now trying to get inbound working (customer calls my number → my Retell AI agent answers). The problem: When a call comes in, my SBC forwards the INVITE to my-number@sip.retellai.com. Confirmed via tcpdump that it reaches your IP 18.98.16.120 — but Retell/LiveKit never responds (no 407, no 401, no 200 — just silence, then my side times out with 487). No inbound call appears in my Retell dashboard logs either. What I've already tried: Both sip.retellai.com and the LiveKit host 5t4n6j0wnrl.sip.livekit.cloud Both UDP and TCP transport Added SIP digest auth on my side (but no 401/407 challenge ever comes back from Retell) My number is imported via "Connect to your number via SIP trunking" with an inbound agent assigned. My questions: For inbound by phone number from a self-hosted Kamailio SBC, do you need to whitelist/provision my SBC's public IP on your LiveKit inbound trunk side? Or does my setup require Method 2 (Register Phone Call API + call_id / middleware)? Is there any way to make inbound work with my existing carrier number without middleware? I need to keep my existing carrier number (I can't switch to Twilio/Telnyx). Thank you!

@AI Evy Answer this

Thanks for tagging me @Brian @ Testzilla.ai. I'll look through relevant sources and get back to you shortly.