Problem to log into game (Arch Linux, Steam)

I have a fresh installation of Steam and Path of Exile, but I am not able to login to the server.

After pressing the "Log In" button I get the message "Unable to connect to login server.". Furthermore in the info box below the gateway selection it only states "Downloading...".

System information:

Arch Linux
Networking: systemd-networkd and systemd-resolved
Steam from Arch repository (installed with pacman)
Proton Experimental (tried Proton 8.* and 7.*)

I was able to get into the game on a different Windows machine.

Is anyone having a suggestion on how to solve the problem? Maybe there are Steam or Proton specific settings to be made, or any settings at my home network?

I already tried dns flush, as suggested in other threads.

Would be greatly appreciated if somebody could help me out.

The login problem is solved. It was an configuration error on my part of my local network installation.

I accidentally forgot to link my stub-resolv.conf in my systemd-resolved configuration, as mentioned in the arch wiki.