Authentication-Problems after Upgrading

Hello,

I have upgraded our RT-Database und RT-Installation the 4th time in the last 10 years. Unfortunatly I run at the last update into problems.I upgraded from 4.0.19 to 4.2.8 Everything seems to be fine - but when I logged in with an privileged User, I haveonly access to the self-service-interface. Also the Admin User I can access to tickets (that are not mine) via the search field.

(Or via the list my tickets) But I am not able to manage tickets. Does anyone have an idea? ThanksPatrick