WPMU DEV DB Plug In - Login not Possible

Hi support team,

i have some trouble with the WPMU DEV Dashboard Plug In.
The Plug In is installed, but when entering the E-Mail and PW information for registration, an error pops up; invalid data.
The log in to WPMU website works.
I'm an elite member.

Can you please check.
Thanks and Best rRegards,
frank