How do I make a preview mesh?

When I try to convert animations to a new skeleton even with the retarget manager stuff all set up, it gives me an error saying that old and new skeleton need a preview mesh, but idk what that is, and no one has been able to help so far. Please help me.

Hi, I have encountered the same problem since yesterday and managed to get a solution on my own. Try finding the Previewing in the material editor under the Details tab. From there, try to search for your assets in the drop down list. Hope it is still not too late…