I purchased a CPE510 back in mid-September to strengthen the signal in my Garage, 100 feet from my house. Setting it up was incredibly difficult but I eventually got it to work. The problem was that it did not "see" my 5ghz wi-fi router. Well, I got it to work via the detailed wireless settings and, actually, it worked REALLY well as a simple repeater. I did a lot of WebEx meetings with VPN as well as used my cell phone at the same time for wi-fi calling. Solid performer. 

But late last week, it couldn't keep a vpn connection and kept resetting. Then I noticed it was showing receiving zero signal. So I brought it back into the house today to reconfigure and nothing. It simply will not find my wi-fi router when I survey, no matter how I configure it, yet my cell phone is pulling the signal for wi-fi calling just fine. Spectrum analyzer is showing -90 db for all three measurements across the bandwidth. I'm in the US so no "region" setting.

I just upgraded the firmware to no avail. 

I'm assuming it's just plain failed. I'm about to pull the trigger on one of those $50 dual band no-name things off Amazon and will aviod TP-Link in the future unless someone can tell me why this thing can't see my router?

I figure this is either something simple, or it failed...