Missing Half Mesh when uploading

[magenta22222]

I have rigged a mesh using marvelous designer- and then blender to rig. I have done this successfully before however now these shorts are visible only on one side when upload to SL. Does anyone know a fix- I have applied transforms- rotation and scale. I am at a loss. 

https://gyazo.com/fc41ca10452c5c2984db50819bd4ca1a

https://gyazo.com/e89a0e7a5da85e9b9e87795be618a55f

That is how it looks for reference. 

[dennis Rexie]

Check if your faces are correct.

When the faces  on wrong side they look dark.

Select all in edit mode and pres CTRL N to fix it