Substance 3D materials working in editor, but not in build

I’m using the Substance to Unity plugin in a new project with only a sphere. I have imported one .sbsar file and set it up correctly and it works in editor and the play preview, however when I try play and build, the material is just white. If I replace the .sbsar setup with a standard material it works fine.

How do I resolve this so my .sbsar materials work properly? Thanks a lot.