Why material shows up as grey tiles?

There are some materials that do not show up in static meshes i import. It happens with materials I import from the UE4 library and also with some materials i create myself.
In the image, the left mesh is the one i imported, and the right one is from unreal. And they both have the same material.

Here is the master material of the one applied. It was downloaded from the UE4 library.

Thanks very much.