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.
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.