Webui wrong password

Hi, I have a strange problem. Every time when I try to login via the webUI I get prompted with “wrong password or username” and get a notification in HA, that a login attempt failed.
However I am logged in via the Hasso App, so I even created there a new user with a fresh password and tried to log in with this new name/password, same result!
Login with this name/user via the app does work as normal
Anyone any idea?

anyone any idea?
Login via App works, same user same password via webUI or via nabuCasa connection: wrong user or wrong password