1. Check to ensure the internet service is working for items with a wired connection.
If the internet is not working, the phones will not work as they use the internet connection to communicate with the phone server.
It is recommended that if the internet is not working that you contact your internet service provider (ISP) or IT service personal for assistance. However, in some cases, internet issues can be resolved by rebooting your network devices (modem, router, switch, etc.). Your IT service personal can instruct you in the proper process for accomplishing this.
Note: In the case of an internet/network outage that lasts for an extended time, some phones may need to be rebooted (by removing the power cord for about 10 seconds) after the internet service has been restored.