Blender object to UE4

Hi,

When I create a model in blender and fbx export to UE4 I seem to be having issues where certain after importing and the object looking correct etc and no errors I save and then it appears in my scene when I try and put the static model in the scene instead of the fbx import root file thing I get the mesh for the static object looking like either a plane or circle ??

I don’t understand why it’s not working right