Currently, Aurora Store, including Nightly (2026-08-31), returns a “&$Server busy, please try again later.” error when attempting to install an application via an anonymous account.

The most important part has been omitted. The problem is that anonymous account is just someone else's account, I suppose, proxied through their servers. So what got blocked are the accounts or the servers themselves, which is shit but not quite surprising.

Non-anonymous accounts are still working as it's much harder to track and block them. They'll try to block them too, obviously, but not yet.