From what you described, this doesn’t sound like a Telnyx issue but rather how inbound RTP is being handled on the LiveKit side. When SIP connects and outbound audio works but inbound doesn’t, it’s almost always a NAT or network configuration problem. In most cases, LiveKit is either advertising the wrong external IP or your firewall isn’t properly allowing inbound UDP RTP traffic, so Telnyx is sending audio but it never reaches your server. I’d double-check that LiveKit is configured with the correct external IP settings and that your RTP port range is fully open in both directions, especially if you’re behind NAT or a cloud firewall. Also make sure SIP ALG is disabled, since it can silently break RTP routing. If you want to be certain, run a packet capture on your LiveKit node, if no RTP packets are arriving, it’s definitely network-related; if they are arriving but there’s still no audio, then you’re likely dealing with a codec or SDP mismatch.