Material/Material Preview Not Showing

Unity Version: 2021.3.18f1

Currently, I’m working with MRTK3 and some of the materials within the MRTK packages are not generating. This includes the preview image for the material in the inspector as well as when it is applied to objects within the main scene. Both projects are using the same version for everything. The first image displays what everything should look like and the second image is what it looks like when the material is not generating. I have already tried copying the material from one project to another and recreating the material with the same properties.

Same issue here.
I’ve been trying every solution I’ve found on the web, I even created a new project, but still I can’t see the materials.

Did you solve it?