operation failed due to geometric condition

I'm working on a drone design. I have 3 parts of the body design, namely the lower surface, the upper surface and the engine compartment. I get 2 kinds of errors when working with the 'intersect' command to cut the geometry that intersects the engine compartment design and the upper surface for the interior design. I got the error in the title after selecting the partitions I want to split. Then I corrected the drawing errors and tried again, and this time I get the error in the 2nd image. Does anyone know the solution and can help? I am sharing the images.