@Urooj.shahzadi It’s the same for me with UE5.4.4. Even the material preview is black. The master material states: “Details cannot be shown: Substrate (experimental) is not enabled for this project (See the project setting window, rendering setting section).”
Activating substrate breaks the complete viewport and the material preview both are covered with artifacts and I’m unable to see anything.
Edit: I’m able to reproduce this. Create a new project by choosing the Collab Viewer template under architecture, then in project settings activate Forward Shading. If you now download a megascan material it will be black.
With the VR template and Forward Shading activated megascans will work. Do you have any idea what’s missing?