Error Code: 0x80048888 - While trying to log in to Xbox Live on Windows 10

"We couldn't sign you into Xbox Live"
"We can't sign you in to Xbox Live right now. Try again in a while. If that doesn't work, we have a few ideas that might help fix the problem."

Sometime in the last couple of weeks I must have gotten an app update for the Xbox app. I have the Game Pass and it won't let me sign in anymore. I just get this message and this error code. The app used to work, and I even have a half dozen installed
games from the app. I have never let the Game Pass lapse and have been subscribed the whole time, so no change there. I have not installed any new VPNs or Antivirus or Firewalls or anything.
I constantly get this error code. It won't let login at all. If I click on the error code it brings me to a blank and useless Microsoft page. I have a Windows 10 desktop that is connected through an ethernet cable directly to my router. I am not on WIFI.

https://support.xbox.com/en-US/search?errorCode=0x80048888

When I go to my Windows Settings>Gaming>Xbox Networking it shows:

NAT Type: Open
Server Connectivity: Blocked

This led me to think the issue was related to Teredo.

I've went to my girlfriend's computer and the Xbox app installs just fine, and I can login to my account on her computer. Her NAT type and Server Connectivity show similar to mine, so I am starting to suspect my problems are unrelated to Teredo.

I've tried mostly everything, including:
Time/Date settings
Xbox Live Status (Appears to be up)
Drivers Update
Windows Update
Windows Store Updates (Xbox app and related apps)
Reinstall Xbox App
Clean Boot (Problem still occurs even in the clean boot setting)
Port Forwarding (I've forwarded the ports related to Xbox Live that I could find)
UPnP (It's enabled)
Other Router Settings
Teredo settings
Windows Firewall settings (It's on and the settings seem correct)
VPN settings (I have no VPN)
Antivirus (I removed Malware Bytes completely)
Network Adaptors (Removed Tuungle and Hamachi)
Multiple Restarts after and between different attempts at changing settings
Probably a couple of other things I forgot to list

I've went through countless posts on different forums and nobody's fix has helped me. I see the problem going back even a couple of years, but nobody has a reliable fix. If anyone has any ideas it would be greatly appreciated. I am looking for help on
here and a couple of other forums, as well as posting as much as I can in case other people search for these terms. Thanks.

:)