Do you have one Space, which is available to "All Users" instead of "Public"?

If so, how could we improve this error message?

I don't think there should be any error message. I just visited a site I don't have access to, so it should just say login or sign up. The error message is about "Spaces" and "your account" which just seems confusing.

I have two spaces, both are "All Users".

I just visited a site I don't have access to, so it should just say login or sign up.

It would say this if policy.allow-public was disabled. As is, the administrator has said "logged-out users can access this install", but also said "logged-out users can't see any objects". These policies are contradictory so we're stuck with the "Drift Aimlessly". I'll special-case the language for logged-out users, though.

(The more-correct remedy is likely for the administrator to disable policy.allow-public or set the visibility of at least one space to "Public (No Login Required)" so logged-out users can see some objects.)

ohh, i see.