Failed to Select Champion??

Okay, so, I've lost my last 4 promos due to this problem, and I have no clue how to fix it. I have fine, stable connection and when It's my turn to select the champion, the timer always says I have enough time. (ex: Timer says 20 seconds left, I'm deciding what to play, 16 seconds remaining, BOOM failed to select champion.) Seriously though, does anyone have a fix to this? I'm not disconnected from chat, I didn't fail to load into the game lobby, I've even tried re-downloading the game. Clearing cache, cookies, anything, I'm literally desperate to not lose my damn promos due to something i can't control.

TLDR: I'm sick of losing promos, how do you not fail to select a champion even when you have time left to pick one?

PLEASE HELP.