Core Issue
There are other users using phones with similar configurations that are able to log in with no problem.
This issue could occur when Extension Mobility is generating the shared line. Refer to the Autogenerated Device Profile (ADP) section of Cisco CallManager Extension Mobility.
If Extension Mobility is set, the ADP is generated. If you set up any profile that has an extension assigned somewhere else, you get the shared line even if Extension Mobility is not enabled on the phone.
Resolution
To resolve this issue, check the Directory Number (DN) configuration for the extension, and make sure the Enable Extension Mobility option is unchecked. Click on Update, then click on Reset Phone. If that does not resolve the issue, delete the Extension Mobility profile for the extension.
For more information, refer to Cisco CallManager Extension Mobility
Removing the extension(s) from the ADP profile also helps.
Note: You cannot delete ADPs. However, you can alter them. Use the delete key to clear out the configuration. Refer to Device Profile Configuration.
Note: Shared lines are not supported in Cisco CallManager 3.3. They are introduced in Cisco CallManager 4.0. For more information, refer to the Attendant Console Enhancements section of Release Notes for Cisco CallManager Release 4.0(1).
