Problem export html5

Hello everybody,
I made an avatar with Mixamo, I edited the mash with Cinema4D and imported everything on Unreal’s Content Browser.
When I play the game, my avatar works perfectly, including animation.
The problem arises when I do an export for html5, open my project on the browser and I can see all my project except my avatar.
Can anyone tell me what the problem is?
(sorry my bad english)
Thanks so much