Using both the client GUI and server command on FabricTailor 1.6.1, I am unable to set the skin using a player name.

It returns an error saying "this player has no skins saved".

I am assuming that the error is because the player specified does not have their skins saved on whatever skin repo, collection, or mirror you're pulling from

Fixed in 6781b91

yes the same thing is happening with me

+1. It's not working yet.