Interner Serverfehler Interner Serverfehler

Weder Craft\EntryModel noch zugehörige Behavior haben einen Scope "competitionTitel".

what is wrong… it works fine til i delete one point in the menu
Somewhere in your templates, you're referencing a custom field competitionTitel that doesn't exist. It sounds like you might have recently deleted it.

It will probably look something like entry.competitionTitel in your template.  You either need to create that field or adjust your templates to not call it.