Supply Closet: "Not connected to Klei server"

[Imas]

I've just come back to this game after a long time, and saw the whole thing about the supply closet cosmetics. But, they just don't work for me.

I'm on the official Linux client.
I've enabled Data Collection as instructed, tried playing for 2+ hours... nothing.
On the Supply Closet menu, it says "Not connected to Klei server", with the generic no-connection-icon.

So, figured I might need to make a Klei account, link that to my steam account.
I just did that, and unlocked a bunch of ONI-cosmetics for free there too.

But when I launch the game again... nope, still "Not connected to Klei server", and everything is locked.

And searching both on the steam boards and in google, gave me zero results of that exact error message (unless I'm dumb). Already verified my installed files, as that was the only thing I could find about this not working (besides discussions about not having a linked Klei account and whether or not that actually matters).

[Imas]

Update: It's a bug with the linux build. Running the windows build through Proton, it just works, but the game lags so much on my machine then that it's unplayable.
Going back to the native linux build, everythings locked again.

[Henlikuoth]

I also have this problem now...
But I am on Windows.

[jupiterLILY]

I am also having this problem on windows