EX7300v2 Extender not found

I've been using the Nighthawk X4 AC2200 WiFi Mesh Extender (Model EX7300v2) for approx. 5 months. Setup was easy and it's been doing the job perfectly. Yesterday, my wifi went out (not sure if it was the actual internet or the wifi extender). Reset the wifi and the extender is not working- perhaps it is what actually stopped working in the first place. 

Of course I called support and since I'm out of the 90 day window, I'd have to pay $50 to have them help me. I tried unplugging it and letting it sit for a minute, and plugging it back in, nothing. For a while, I kept getting kicked out of the Nighthawk app and was told my password was incorrect (whole other issue as the instructions to reset your password take you in a giant circle because you can't actually get to a login page that allows you to reset password). 

Anyway, the app seems to be working a bit better, and I've tried a factory reset. The light that indicates connection from extender to mobile device is on and solid green, but the light that indicates connection between extender and the router is off. In the Nighthawk app, when I try to connect to the extender, it says extender not found. I'm at a loss on how to proceed, I reset the modem and router hoping that would help the extender connect to the modem but no such luck. I'd appreciate any help or suggestions. To my knowledge there have been no changes to our ISP or the router or modem.