Client closes saying "session expired" very very often

When i log in often i get this unexpected error, i get it when im in the client and im doing something, in lobby, in champ select, and in game as well. It then quits the game to the desktop and i have to log in again, and ... it can be a pain in the ass during clash and ranked you can imagine... I have deleted and reinstalled the game already, for everyone saying i should do that. I also get errors when trying to join my friends groups via friend list join, and when accepting invite, and have to click like a gazillion times to get it to accept, when it does its still buggy, and sometimes i have to restart the client to get it to accept. I already sent like 7 bug reports etc, no help yet.