What are you using for authentication when connecting to RUT241? Did you make any changes to the Hotspot page or anything similar? It seems that there are issues reading some of the credentials on the login form.
The issue is with the password provided on the authentication page (or its hashing).
If you are sure that you did not change anything, and you add users in Services → Hotspot → Local users, but still receive this error, then it might be that something in the hotspot package that got corrupted. Please, try removing the package and reinstalling it.