sometimes when i play online my replays dont work why does this happen?

Press P, it sometimes pauses them

Yeah it happens to me also sometimes when i play online, after the match the fucking replay won't start, it is just freezing a screen with tori and uke -_-. How Billy said try to press P sometimes work.

Check the replay speed, probably it's set to 0.
Sometimes the new game just starts right after the previous ends though.