7960G SIP phones do not register if they are not directly connected to the Cisco CallManager Express router. The registration attempts fail and the Contact doesn't match any pools. debug error messages appear.
In order to resolve this issue, complete these steps:
Add username cisco password cisco under voice register pool 2 and configure the same on the phone.
Unlock the phone. The password to unlock it should be cisco then in Settings > SIP Config > Line 1, change the Authentication Name and Authentication Password to cisco in order to match the configuration under the pool.