Issue with edited mesh [SOLVED]

I edited a mesh for the first time ever and though it looked nice in Blender and S4S, when I went in game there was an issue at the bottom:




Can anyone tell me what went wrong and what I should do to fix this? Here's the blender file.
I edited the knight armor mesh and converted it into a top using a nude top.

EDIT: Nevermind, I managed to fix it. So sorry for the trouble!