I have a very simple low poly mesh that was created and animated in maya. The mesh is already triangulated, but when trying to import it into Unreal it gets stuck on “triangulating mesh” and Unreal becomes unresponsive. I’ve successfully imported several other similar meshes and they worked just fine.
This folder has both my fbx and the maya file used to make it:
If you are able to import other similar meshes, that indicates that there is a problem with that particular mesh or your system and not the editor. I notice the UVs seem a little weird on the deer’s leg. This may not be relevant, or it may mean you may have to fix some irregularities within your model like non-planar faces, concave faces, faces with holes, etc.
BTW. We’re running Maya 2014, so if you have a later version that would be why I couldn’t open your file.