Quoted from PinMonk:
Yes, but what exact model and version (if available) is printed on the router?
I'd try limiting the router to wireless g and one frequency (2.4Ghz first) and one channel (6 or 11 are best). Then see what you get for a connection. If you still can't connect, switch just the frequency to from 2.4 to 5Ghz only on the router and try again. You have too many variables, so you need to restrict them on the router side to find the issue.
Netgear Nighthawk XR500. I appreciate all the solutions I’ll give it a whirl!