I want to put this somewhere a search engine will archive it, because I had to really search for this, but if you're having trouble with Payday 3, Remnant 2, Halo, Minecraft, the Microsoft Store, or Astroneer, and you have at any point had McAfee installed on your computer, even if you uninstalled it, and you've noticed that the internet traffic of those games is being redirected to ip address 45.0.0.3, port 3128, then you can open a run console as admin, run "netsh winhttp reset proxy", reset your computer, and it should work. You might also have to reset your winsock and ipconfig, whatever those mean... I'm not really a networking girl.
Major, major thanks to user nataliswolf on, of all things, the 7 Days To Die forums. This problem has been plaguing me for a year, and absolutely nothing is more frustrating than when you want to play a new game with your wife on your date night and it straight up doesn't work.
I suspect that it only hit games with some kind of external verification service - anything where I had to sign into an account failed just like this. Strange.
