You have a computer connected to your router by an ethernet cable, and the computer is not connecting you to the internet.
Make sure:
The router is plugged directly into a working electrical wall outlet (not a power strip) and the power cord is connected securely on both ends.
The cable connecting the router to the Optic al Network Terminal (ONT) is connected securely. Your ONT may be mounted on a wall in your garage, a closet, or outside.
The ethernet cable is connected securely to the computer and the router.
If you've reached this step, your computer can access the internet now that you've plugged your ethernet cable into a different LAN port on your router.