15-7A unable to load

I guess its worth mentioning that i too am on PC, but I did manage to get online to play. There are indeed alot of people still playing. I gave up trying to launch the game via steam on my PC but instead launched the game via Geforce NOW. I didnt think it was going to work until it did! The connection was horrible and I was only able to play for the 1 hour they provide for free until you get kicked. Logged into my steam account and sure enough i got in. Try this method although not an exact fix it is a work around. Something tells me that there is some nefarious work at hand, I too am on AT&T Fiber and was able to play this morning. but on Geforce NOW you'd be playing remotely from a Nvidia server somewhere. Just look up geforce now and signin to your account. please do let me know if this works for you as well in the meantime.