HTTP 500 Error when logging into CCX Editor - but only certain users!

[pescla]

So two admin user we always use on a customers environment suddenly throw an internal server error when logging in. Some other admins work fine, but some - tried on multiple clients - do not. What could possibly cause this?

[pescla]

To make things even weirder, we discovered that new users that we create recieve a 401 when logging in.

also, for users that have a working login, when we change the PW in the AD, the webgui login works with the new password - but the editor login doesnt.