There were some perspective scenes in the project that were made before I installed the Condoc extension. With the LT drawingset I could make elevations, sections and perspective drawings, so I did not understand why no floorplans. Today I deleted the old perspective scenes and now I can make the floorplans too. So the problem seems to be solved.
I’m working with SketchUp 2020 and ConDoc 4.8.1