N300 EX2700 Wifi Extender Green Lights but No Internet

I have been using the N300 EX2700 Wifi Extender with a Linksys E1200 with no major issues for a couple of years, but now I'm having a problem I've never encoutnered and can't seem to find any support online for:

Details of Problem:

I had a power outage while I was out on a short trip, so it's possible my internet has been problematic since then. Upon returning, the EX2700 still extends the network and the the _EXT SSID is still available, and all the front LEDs are green...

But when I try to join the network with any device (phone, laptop, iPad, PS4), the device connects, but shows "No Internet Connection" and does not have internet connection.

Things I've Tried (that didn't work):

- I rebooted the modem and router and extender

- I factory reset the extender and went through the setup process all over again

- I updated the extender firmware (since the extender stopped working before the firmware update, I don't think this is the cause of the problem)

One Thing that "kind of" worked:

- After factory reset of the extender, I set it up in the same room as the router. After setting up, I was able to connect to the _EXT network AND able to access the internet (at a slightly lower speed than the router's network).

- HOWEVER, once I moved the extender back to where I've had it for years, it stopped working and gives me the No Internet Connection error, despite having green lights all across.

The place where I had the extender does have pretty poor signal of the router network, so I would normally have just assumed it was out of the router's range... BUT:

- all the lights are green

- I had the extender in the exact same location for year without problem

So I'm confused.. any ideas?

Thanks!!