You have a problem.
The move of Passwords was not completed.
The result has been that there are members who will be able to view the entire site as they did before but because the Passwords have not crossed correctly when that full member attempts to view the entire he/she cannot.
The solution is to 'logout' and log-in totally afresh.
It looks from here that a memory transfer threshold was reached and those beyond it are only given the initialised password for the opening page.
The remainder will be on the old set-up somewhere.
I suggest that on the Public page a contact email is set up for those that fail to gain full access following the simple solution I've outlined.
Edit... yep, you must log-in from a 'clean page'... go to google, look up 'stuttgart9s', go to front page, log out there, then leave that page to any other site/google, then return and log-in as if it was your first time.