Problem enabling user for Project/program TOC

Which Innovator version do you use? I remember this one from 12SP17/18. It´s basically a conflict that happens in the "Client Style" tab at the right side of the ItemType (no idea how the tab is called in your language :) .

You add one of the identities and Innovator updates the CUI definition and presentation config in client style. Looks like Innovator wants to add the initial section, but it already exits. Around 12SP17/SP18 Aras did some restructuring and renaming of the Presentation Configs which sometimes made trouble with custom stuff by users. 

Do you use custom CUI elements on projects? The solution is to delete the conflicting element. BUT: I am not sure whats inside your definition and if there is something you might need. So either do a test in a test database first or provide some screenshots of whats inside your Client Style tab (if you want to go with the screenshot solution, also provide screenshots of whats inside the specific elements). 

Edit: As far as I remember the behavior mainly happens when you have TOC Views.