Can anyone tell me how to fix Lol client closing randomly during champ select?

My problem can be see on the screenshot I sent. Recently my client closes randomly without any explanation. It used to happen to me when I finished a game, and I got directed to the lobby. But nowadays it started happening to me during champion selection. This error or bug occured almost daily in the past few weeks, i cant even remember how much lp I lost due to this. Today I had to face this issue twice, now I have 15 mins of ban and lost 10 lp. So while I'm waiting I thought maybe someone here could help me with it. I tried to reinstall lol, but it didnt help, and I didn't find any useful guides about this. Does anyone know the solution?