You should see something immediately before that in the logs along the lines of “Call has exceeded it’s permitted lifespan, cancelling.”. Each call has two potential timeouts: one that limits how long to wait for someone to answer, and one for how long the phone call can last overall (to limit the damage should the hangup fail to be detected. We haven’t seen this, but phone systems are weird). This type of error is bound to happen when either of them expires.
Ultimately the question is: was the timeout legitimate, or due to a problem? Have you tried to make a call again? Even something as simple as a wrong number could lead to this. As you test, perhaps keep a tab open on Status>Voice Alarming, with “live values” turned on, so that you can watch the call progress. See if it goes through the cycle of Ringing, Talking, etc.