If this is an issue with all of your IP phones, then you should be looking at the Personal Directory configuration in element manager.
If it is an issue on some phones, then you should be looking at the call log options on those sets.
To enable Personal Directories in element manager:
Go to System-->IP Network-->Personal Directories-->Server Configuration
Make sure the E-LAN address of your leader signaling server is entered in the Server IP Address field.
In your Node configuration go to Node Details-->Personal Directory (PD) Configuration and make sure the check-box is checked.
If necessary, check the check box, save and synchronize your node and you should be good.