"Windows was unable to connect to" 5 GHZ

[Demo_Beta_v2]

I just installed a new router (WNDRMACv2) and cannot connect the 5 GHZ channel (TP-Link N900 PCIe card). All firmware/drivers are up to date.

The 5 GHZ channel is detected, I can try to connect, enter the password, but then I get the message "Windows was unable to connect to...xxx."

My question is this: Am I just out or range of the 5 GHZ channel or does this indicate a different sort of problem? I would expect Windows to at least connect to this channel and then give the "limited or no connectivity" message, but it never gets that far.

I don't have any other dual band devices so my next option is disconnecting the PC and lugging it up a flight of stairs to sit it next to the router, but I'm hoping to avoid that

 

[Demo_Beta_v2]

Okay, I moved the PC to the same room as the router, about 10 feet away, and it connected right to the 5 GHZ channel; it seems to be working fine and at speeds 10 Mbps faster than the 2.4 connection.

Anyway, I'm now confident my hardware is working properly, but I'm left wondering this: Why would the 5 GHZ connection read at 2 (and sometimes 3) bars of signal strength yet be unable to connect from my PC's normal location at about 40 feet and three rooms away?

 

[PickyPerson]

I have the same problem but in my case it just stopped connecting one evening