Hello. I’m a Korean. The sentences are awkward using a translator. Please understand.
There is a bug where the mesh is not visible in the engine.
There is no mesh when android preview is on. When you turn off the android preview, the mesh is visible.
Looks like there is a problem with the scale of the mesh because vertices are there(13k it says.) Export as FBX version 2014 if you havent already and reimport.