@doulos4iesou Yeah, sketchfab doesn’t support Cycles materials, so they say you have to bake everything out. I’ve run into similar issues. I know in some hidden tutorial that I watched but can’t remember which one here on cgcookie where they go over how to bake things. But here’s how it works on the sketchfab end.
https://help.sketchfab.com/hc/en-us/articles/202600873-Materials-and-Textures