How to Resolve "DHCP Failed" Reading/Issue on Phones:
1) Make sure that any and all connections to both the phone(s) and the router are secure.
2) Reboot the phone(s) by simultaneously disconnecting the Ethernet cable and power supply (when applicable) on the underside of the phone, and then replacing them in the same ports from which they were pulled.
3) If Step 2, rebooting the phone(s) does not resolve the issue, please reboot your internet router first, and then reboot the affected phone(s) as described above.