Installation of OpenProject fails with Unable to locate package univention-postgresql


I am trying to install OpenProject form the App Center but the setup fails. From the log file I have seen that the setup of postresql fails with the error " Unable to locate package univention-postgresql" but I have no idea how to install postgresql. Every attempt fails with the above error.
The UCS was upgraded from 4.x to 5…

Any help would be appreciated.

Thank you.

Rgrds Chris