First, determine the scope of the problem. Try another website or application that uses the internet. If the other applications work, it could be a problem with the one site or program.
If the other page/applications do not work, check your other devices. Do they have the same problem? If you connected using WiFi, check a hard-wired connection as well. If not, the issue is local to one device and your internet service is working. You might want to restart the device in question.
If your other devices also do not connect, reboot the router or Remote Gateway (RG) that allows you to connect multiple devices to the internet. You can do this by unplugging the power, making sure the lights go off on the router/RG, and wait about 20 seconds. Plug the power back in and wait approximately two minutes for the device to establish a connection. Then try your internet again.
First, determine the scope of the problem. Try another phone to see if it has dial tone. If you are using a multi-handset cordless phone system, be sure to try a phone that is not part of the system. If another phone works, it could be a problem with the single phone/handset.
In order to rule out bad wiring or a bad wall jack, move the working phone to the location of the phone in question. If it works, the wiring/wall jack should be good.
Now, that we know you have dial tone at that location and the problem is isolated to one phone, troubleshoot that one device. Try it at another wall jack using a phone wire that you know works (from one of the other phones). If the phone is a cordless unit with a base that plugs into an electric outlet for power, we can power cycle it. Place the handset on the base unit. Unplug the power cord from the base unit, making sure the lights go out, and then plug the base back in. Wait about 20 seconds for the device to power up completely and then check for dial tone again. If the phone is part of a multi-handset cordless system, you’ll want to also power cycle the main unit before powering the remote base back up. Just follow the same process.