WinRM Negotiate authentication error

OK so I'm trying to build a standalone windows 2016 hyper-v server and manage it from a windows 10 workstation. I have installed RSAT and built the hyper-v server (free edition with no gui). I can ping the server and RDP to it etc but when I try to use server manager on windows 10 I get "WinRM Negotiate authentication error" all the time. Can anyone help? I've already searched and tryed lots of things.