> Model: R6020|AC750 Dual Band WiFi Router
> Kicks out internet when connecting to modem. [...]
What, exactly, does "Kicks out internet" mean to you?
Whatever it might mean, it does not say what you did. It does not
say what happened when you did it. As usual, showing actual actions
(commands) with their actual results (error messages, LED indicators,
...) can be more helpful than vague descriptions or interpretations.
> [...] any suggestions?
A useful problem description might be a good start. What is your
"modem"? What, exactly, is connected to what?
Visit http://netgear.com/support , put in your model number, and look
for Documentation. Get the User Manual. Read. Look for the LED
descriptions and "Troubleshoot".