XFi Gateway, Windows 10, Can't Connect Error

Whenever I try to connect to my Xfinity xFi gateway WiFi on my Windows 10 PC, I am prompted to input the password (again) and then it just says "can't connect to this network."  I'm sitting at the PC with my tablet and phone both connected to Xfinity with no problems.  My old Vista PC connects.  My Windows 10 PC can connect to my phone's hotspot with no problems.

I have restarted the computer.  Many, many times.  I verified the heck out of the password in the WiFi Bands part of the Xfinity app.  I have done WiFi and airplane mode on and off.  I restarted the router. I have Forgotten the networks and also tried putting them back manually.  I have uninstalled the driver and restarted.  It says there are no driver updates. I have reset the network adapter.  I did that thing where you enter command prompts to reset/renew the IP and flushdns.  I found some advice about advanced network settings and a mode (between the a, b, g, etc stuff), but no changes helped, so I put it back on Auto.

My xFi is new, but my PC DID connect to it at first, one time, a couple weeks ago, and never again.  

Tldr, ALL devices but PC connect to xFi, PC connects to OTHER WiFi only.

How do I make my PC and xFi friends?