Connecting to OctoPrint WEB-Site login does not accept Username and/or Password

[xIExodusIx]

Hi there,
I installed OctoPrint 1.0.0 RC3 via RaspiImager, with SimplyPrint-plugin. On a RaspberryPi 2B.
After the first boot and going trough the User setup, everything runs fine.
Logging out and relogin dosn't work, my Username and/or Password would not be accepted!
I had to click on "Forgot Password" und follow the instructions to reset the Password via ssh using the same Password as before.
After that I can login, until the next logout, then I have to reset the Password again. Why? Whats going wrong here?