The call session itself failed — SIP signaling could not complete or was terminated abnormally.
The RTP audio path terminally failed during an active call session — ICE collapsed, TURN allocation lost, media could not be recovered. The call is effectively dead from the agent's perspective.
The media path was interrupted but the call session is still alive — a transient glitch that may recover or may terminate.
Events when the ACS SDK signals call failures or media disconnection/failures.