This is the status messages on the IP phones:
NO DNS Server IPXML Default.cnf.xml File Not FoundSEP.cnf.xml File Not Found
Verify the Dynamic Host Protocol Configuration (DHCP) settings before performing the resolution steps. Refer to Troubleshooting the Cisco IP Phone.
To resolve this issue, perform these steps:
If you continue to have problems with a particular phone, the configuration file might be corrupted.