Same issue here. Yesterday afternoon game was working perfectly for me.
Since today's patch, game has been acting up. Thought it may have been some internet issues. Restared router. Reinstalled the game, checked for corrupted files. Even tried another online game to check everything was fine. (I could play the other game without any issue.)
Nothing worked so far.
I can actually enter the game, but there is no consistency while playing. I can go from not having any problem at all to having 1-3s delay, and sudden DCs that last for several seconds, and then evrything works.