First, try turning the phone off and on again. If that doesn't work, unplug the phone from the wall and plug it back in. If you're still having problems, call your telephone service provider.

First, try to isolate the problem. Reboot your phone system and/or your phones. If the problem persists, then you'll need to start checking the wiring and connections. Make sure all of the cables are plugged in securely and that there are no broken wires. If you've checked everything and still can't find the source of the problem, then it's time to call in a professional.