I am trying to import a static mesh for the engine, but the custom collision is not working.
In Blender, you must use the same name in the suffix of your collision mesh as the name of your model like so:
Make sure both the collision mesh, and your model are selected when you export as well (They should both be in the same .fbx file.)
Try this tutorial made by fighter5347. from my old Posted here “Stair FBX/OBJ import use in UE4 - Pipeline & Plugins - Epic Developer Community Forums”