I have call manager 7.1.3 and have 7975 ip phones. I configured an CIPC and all worked well that is incoming and outgoing calls etc. then using the tokens, i created the CTL file and the enabled the mixed mode for the CUCM. After this i added 7975 phone and i got the auth fail message so I did the process of dual upgrade from the 8.3.2 to 8.5.2 and then to 8.5.2sr1. during this i removed the CTL file(deletd from the CUCMs and the IP PHone) and changed the mode backl to the non secure mode. I configured the same directory number on the CIPC as on the 7975 phone. strangely the call goes thorugh from the CIPC but not from the IP Phone. incoming call rings on both the devices.