The past few times I've tried to play online, when I get to the 'please wait' stage with the Sandbag the game stays there until someone leaves, and I don't get to fight. I don't know if this is a common problem, but is there any way to fix it? I've tried both high and low latency.

The downtime tomorrow should help with this (hopefully), and you will see an improvement (hopefully) after it's over

if not, let us know

Same here, and sometimes the screen freezes or goes black in the middle of the game.

I am getting the same thing :/ the downtime, it fixed not thing D:

alright. we have yet to narrow down what's causing this and we don't have any leads so don't expect any immediate fixes.