Well, I've never seen this one before.
Can you copy-paste the output of `env | grep -i proxy` ? (Just run it in gnome-terminal, select, Ctrl+Shift+C to copy, paste it here)
Hm, actually I got absolutely nothing back from that command.
Also I tried starting Itch again today & it works, so that's nice. Although I wish the solution to this problem was clear, it's okay though. Thanks anyway, Amos!!
That one shall remain a mystery for now. Happy you got it working :)