Can't load into matches properly - Time Skew Max leads to crash/disconnect

I was able to play the first day of the Slam fine without any crashes or hitches. Played it for 6 hours straight with zero problems whatsoever. Go to sleep, turn off the PC. Wake up next day, Turn the PC on, launch the game - and suddenly the game barely runs. Getting into the Menu is fine but anything after that runs horribly and I can't actually play any matches because it gives me Time Skew Max error, like the game was running at such low frames for so long that is was unsustainable. Can't get it to work properly now like it ran today. What happened? Drivers are updated and Windows is aswell. No system or software changes were made.