I've tried resetting my internet, redownloading the game on another hard drive, downloading and starting the game from maniaplanet instead of steam, tried changing settings in the launch options "PeetToPeer" as well as "Network".
Also something that i tested was downloading the game on my laptop, where the problem did not occur. So i do not think that it is a network issue.
viewtopic.php?f=264&t=41169 I found a post where someone had the same problem as me and i tried their solutions but nothing worked.

If you have a solution to my problem or any idea of what could fix my problem it would be greatly appreciated! Thanks in advance.
-Hardware (Nvidia GTX 1080, Intel i7-4790k, 16GB Corsair Vengeance RAM)
-System (Windows 10)
-Network (Fiber 250mbit/s up & download)
-Default browser (Chrome)
-Antivirus : Windows firewall and Windows defender