Cannot use browser while Call of Dragons is open

As soon as I open the game and want to register with my Google account, then my Browser opens. But my browser says I don't have internet. I can't open YouTube either. I don't have any internet problems. I have a roommate and he has no problems either. Discord also works. My browser is up to date. Opera. Google Chrom does not work either. I did a BIOS update and it didn't help. Unfortunately I don't find anything on the Internet. As soon as I Close Call of Dragons, the browser goes again immediately like normal. Also tried with discord closed. Reset Opera, cleared cache, blah blah. I also changed the internet settings with a colleague. It didn't change anything.

I dont know what to do...

Oh, and by the way: When I once tried to buy a game from G2A, my browser stopped working for like 5-10 minutes. Neither did Google Chrome nor Explorer

Mainboard Asus Rog Crosshair X670E Extreme

Gigabyte 4090 OC

G.Skill 4x 16GB

AMD Ryzen 9 7950x 16-core processor

SSD Kingston SA2000M81000G