Texture turns dark in viewport and after Building Lights

[Hybreed_1 (AjitRG)]

Hey Eric,
I’m attaching the UV layout Screenshots and FBX files!

This is the Dropbox link for FBX Mesh, kindly have a look.
https://www.dropbox/s/87v8ufei5lpkil9/FBX%20Mesh.rar?dl=0

Thank You!