Hi @redwanpranto15,
Your geometry has a multitude of problems. The obvious ones are shown below.
Your gears are sticking out of the body and the top surface has effectively zero thickness and is pretty much just an empty shell. Ensure the gears are enclosed fully and the top surface has some thickness and the gears are just mated to the body in an assembly. Refer to the mesh can you can see that the top surface was not even meshed due to the shell like nature of the top surface. In fact throughout the whole body, it is just an empty shell. I suggest having a certain thickness to the outer body to reduce these meshing problems as seen below.
Another issue is the obvious lack of an MRF rotating zone. To define a rotating zone you must have the gears inside a circular, enclosed, watertight solid zone as a separate part. If not you will encounter meshing problems and you will not be able to use an MRF let alone an AMI.
Resolve these issues in CAD first and we can proceed from there.
Cheers.
Regards,
Barry