Ranked Champion Select Bugging/Lagging out

I've been getting an "Unknown Error" window during Chamption Select.

Nearly every time I try to play a ranked match, I will get "lag" in champion select; to me it will appear as if the timer has run out on someone's ban, or turn selecting a champion, but it won't move on to the next person's pick/ban turn. It will sit there.

Sometimes, nothing will register for me visually until a minute or two later, when more bans and/or champion selections of others have been made.

A lot of the time the lag lasts so long that I get kicked out of games. It will be my turn, but the screen does not register this. It shows that it is still someone else's turn to pick/ban but the timer has run out for a long time on that person's turn. I try to click a champion, but the stupid thing doesn't let me because hey, it's not my turn! This is usually when the "Unknown Error" window shows up. When the lag finally ends it will be too late and I'll have been kicked out of the game for failing to choose a champion. I've lost like 3 promotion series this way, and loads more LP.