So I am new to blender, I want to create a flower to show on my web page. I imported a model from the poliigon, and also a texture. The problem is, the texture / colors are not visible when exported, although when rendered in blender, they are. Why is that?
Here is how it looks in blender:

and this is how it looks in 3d viewer:

why is this happening?
**EDIT **
this is how the shading part looks for the upper part of the flower:


