"Failed to connect" Unable to connect to the server. Loading screen bug.

(Sorry for my bad english) Hello Riot/Community,

I am having an issue wich occurs after championselect and won't let me get into the loading screen. The games end up being remaked because I can't connect to the game without getting this annoying error pop-up every single time. I have been punished 2 times with the leaver buster now and lost around 60 LP to this. After the first game I tried it out in a custom game after disabling my firewall and restarting my client. It worked. After that, I decided to start another ranked because I thought it was fixed. It worked. But I had several "Attempting to reconnect" pauses where I couldn't move and simply died every single time... My internet works great and I can play all kinds of other games without any issues. I ended up losing the game for me and my team. (Even though I couldn't do anything for it.) After that. Played some Normal games after that. Some worked, some did not.. Weird... I rebooted my PC completely and reinstalled league, installed windows again, all drivers for my graphic card/internet connection, direct x and the windows updates. When league was done installing I tried to jump into a custom game. didn't work. If anyone has a solution for this, or any tipps, I beg you... Please help me with this.

It doesn't seem like I am the only person with this problem. I found this thread, but nothing useful in it. https://boards.na.leagueoflegends.com/en/c/bug-report/MJ5G4gNm-unable-to-connect-to-server-please-check-your-network-connection-and-attempt-to-reconnect