An error that happens to me after i delete the intial cad model from the external flow region

I am trying to use the incompressible flow simulation to test the air flow around a stl file of a plane.

I have been getting an error when trying to mesh saying there is a error when trying to mesh saying there is self intersecting parts, I have been getting it after a lot of trial and error from previous errors to reach this point, and from my understanding I am supposed to make an external flow region around the stl file, then delete the intial cad model from the cad since it is 2 different objects and its not allowed, then i deleted the intial cad model from the flow region with the heal method(i tried the other ones too).

and then i have been getting this error when trying to mesh after deletinge:
The meshing failed due to a self intersection in the mesh on the following entities: face 71@Flow region, face 71@Flow region. The exact position is printed at the end of the Meshing Log. Learn more.

and here is the meshing log:
Code: 1102 String: Cannot resolve intersecting mesh between face 7 and face 7 at (-13.412493824232302, 47.31991244291622, 24.720040521355294), model may self intersect

how do I solve this error and successfully mesh my flow region with stl file imprint in it?

Hello, it appears that you have been able to get a successful meshing operation in the meantime.

Feel free to share details on what you did, in case other users run into similar issues.