Design dyson roller with unknown broken area I am new in Blender, and doing hard to learn that. I was trying to made a Dyson vacuum cleaner parts by Blender and I made it, but the final model has a problem that I don't know why and how to fix it.
This is what it looks like in the object mode, I saw this problem after I have add solidity and subdivision on it:

This is the rendered image with clear broken area:

This is what it looks like in edit mode and without solidity and subdivision:

In my mind I haven't made any N-gon in these area, so I don't know why it happens, could anyone tell me the reason of that and how should I avoid on next time?
Here is the source file:
Blender File
Thank you very much for reading this thread.
After viewing your model, here's what I did:
#select the meshes then ctrl+A to apply all transformation.
#select the object go to edit mode and select all the vertex by pressing A once or twice. And then shift+N to recalculate normals.
Your mesh had some flipped normals which caused the issue you marked.  Here's the File after applying the fixes I mentioned.