I just got an issue with 3 users/telephones (7940's). When I was trying to call their extension, I received a busy tone while they were available. Issue was resolved by restarting them from the callmanager but I want to know what could have caused this in case this issue repeats.
Additional info: these 3 numbers are member of a hunt list of 4 numbers. The 4th number didn't had any issues.
What could have caused this?
Thanks in advance!