I have 3 different Cisco 7940 phones that do not show the services when pressing the services button on the phone. Services are configured correctly as are the switch ports. Phones are functional and are registered with a call manager. When resetting the phones a message "error verifying config info" flashes briefly. When pressing the services button on the phone error "host not found" is displayed. I have taken a phone with the same services configured and connected it to the port that one of the 3 phones doesn't work and it retains its settings. Any help will be greatly appreciated.
i don't know whether the phones are manually configured or configured via dhcp, but it you've configured manually, you may check whether a valid dns server address was enterede on the phones.
one thing to try is to clear the current config on the phone, unlock the phone go to settings, network configuration, erase configuration change to yes then reboot the phone
we had this problem when we moved phone from one site to another ie different call managers