Check whether calling and the intended trunk are enabled, then review the returned refusal or media error. Routing, authentication, codec, and transport mismatches need different corrections; a connected signaling session alone does not establish working audio.
Record the call reference, time, transport, and redacted response code. Compare with your own trunk logs. Disabling number calling blocks new calls but does not end calls already in progress. Ask support about the specific failure without sending SIP passwords, full target addresses, recordings, or private customer details.