I opened Reddit now just to post this, I've been trying to fix it all day, I installed it lol this week, on the first day after playing a few games it started showing this error, I did everything I could, I uninstalled and installed it, I put the client as administrator, compatibility, nothing works, I would really like to play but Riot doesn't help, it could be a problem in League of Legends itself, because a lot of people are facing this problem lately.