Rigged avatar not displayed on iPad

I have an avatar (fbx), that was rigged and exported using Mixamo.
There are no animation on the avatar. It’s only the T-Pose.
It was difficult to import it in the editor because we had to solve many errors, but in the end we’ve managed to import it.

Now we have another problem. The avatar is not showing up in the iOS device (an iPad 3), but it’s visible on the desktop app.
Any ideas?