In single region simulations, only the fluid region can be assigned to a material

I need your help, I’m getting such an error mentioned on the heading of this problem. The Meshing was successful, but the simulation run failed showing that error. The geometry is a SolidWorks Assembly file. Your help would be appreciated.

The project link is below:

Hello sameer_malik19,

please have a look at this article on how to solve this error:

If that doesn’t work for you please reach out back to us.

Best regards
Sebastian