Core Issue
When trying to use the address book and fast dial, the service fails. The personal address book fails with this error message:
Error-7ffbc5c2 User (None) was unable to be validated (14910). No phones in the network are operational using this function. Currently this system and the services are not working.
This error message indicates a wrong pin number in the PAB service.
Resolution
If you encounter this error message while accessing the address book from the IP phone services menu, log on to the Cisco CallManager user page (http://(ipaddress of Cisco CallManager or CallManager user) for the user having issues. Make sure the PIN is set correctly.
When you configure the address book service, specify a PIN. The PIN from the Cisco CallManager user page should match the PIN specified when service was created. Make sure that the PIN configured in the global directory for the user is correct.
For related problems with Personal Address Book (PAB), refer to the document When the user presses the Services button to access Personal Directory Fast Dials, the -7ffbffcf: User (3177) was unable to be validated. (49) error message is displayed
This error message can also be related to the TelAppSupportX.dll file located in the c:\program files\cisco\bin directory. If any of these problems appear, it is best to replace the file with the latest version.
To obtain the latest TelAppSupportX.dll file, refer to the TAC Service Request Tool to open a service request.
Fro more information refer to Troubleshooting Personal directory with Cisco CallManger 3.x and 4.x
