[GAMEPLAY] not being able to connect to the game

I tried to play ranked flex earlier and after champ select was over I could not connect to the game despite having perfectly fine internet. I have lost lp due to this and I now have a 20 minute low priority q from failing to connect twice after trying to play a blind pick game. One thing I found that worked is restarting my comp but unfortunately by the time I'm getting into the game my team already remakes. I do not have a clear idea of what causes this bug, or if it even is a bug, so I cannot give an accurate procedure, but instead explain what took place before I was not able to connect.

1. I queued up for flex and picked rakan
2. I (accidentally) took a rune page titled "Riven"
3. I (also accidentally) took a mastery page titled "Riven Riven" I waited for the game to start, and the loading screen to pop up, but instead I received a message saying something along the lines of "failed to connect to server, please check your internet connection and retry"