Inbound call has dead air or delayed audio

Detailed solution

1. Step 1Use one approved test, or a read-only aggregate report. Record the exact time and affected scope before changing anything.
2. Step 2Reproduce with an internal test endpoint, then have the network owner verify the negotiated RTP path, NAT policy, and firewall range for that one call.
3. Step 3Change one owner-approved telephony setting only, repeat the same test, and verify both call legs before closing the issue.