We recently upgraded one of our clients from CCM 4.2(3) to CUCM 8.6(2a). All seems fine except for the fact that certain 7911 IP phones are expriencing a strange problem. For any calls (internally or externally originated) some of the 7911 phones ring normally, but lifting the receiver does not answer the phone call. The user has to press the speaker button to answer the call, and the same to hang up. Any ideas on what may be causing this?
Thanks in advance.
I would suggest upgrading their firmware to the most latest firmware version available i.e. 9.3.1 SR1 found here & see if it helps.