Thanks @Yujia Wang for your answer. I still couldnt solve the problem.
I indeed have the reference lost error (2269272). But everything is installed on one system (so no seperation beetween frontend and backend). I played a lot with the system aliases, i suppose the problem is regarded to that.
But I don't really get a hint from the frontend (this error message appears also on other apps). Since its an WebDynpro application, I should see somewhere a link which webdnypro is called like it is done in Fiori and then i could debug and check what the error is. Is this somehow possible? I have no entry point to come closer to the error :-(
Thanks and regards
Chris
