All accounts on the site have been logged out, and will require logging back in.
We've seen a number of very old (5+ year not logged in) accounts get broken into over the last few weeks and out of extreme caution, I'm are rotating our "primary key" which is used to authenticate accounts on all of our sites.
As always we recommend keeping your password updated yearly and using a password manager (your OS probably comes with one now!) to generate strong passwords, and do not reuse passwords. In most cases, these situations happen because another site is hacked their database is leaked to the "dark web" and folks use the same email/username/passwords in multiple locations. If you feel like someone might have access to your Subeta (or any!) account, change your password right away.
We're always watching out (👁️) and have invested time recently in tools that can "unwind" an account getting hacked and drained. Please make a ticket if you find that you are missing items, or think that your account has been targeted.
You can also check on https://haveibeenpwned.com/, a website to search for your email in large scale hacks on the internet.

Chances are a lot of those old PWs were shared with Neopets logins, since Neo had a GIGANTIC password leak around that time.
If anyone plays or played Neopets and uses the same PW on both sites, change it immediately!