First of all. Ty for the reply.
That is a good point. Maybe I also should give some more information.
I created an Ubuntu Desktop image in Hyper-V. On that machine I installed UCP and DTR. Since they both rely on Linux images(?). I then tried to pull the windowsservercore image from the public hub to the registry through UCP. When I try that I get the Blob error.
We want to have 1 central registry with all our images in it so we can pull and push from different sources. Local Environments, Servers and automated systems. So we would like to have all our images reside on a central registry. In this case the DTR.
We have tried to push and pull from Window Deamon to Nexus. This also resulted in an error (Directory not found).
From what you are saying I should setup a Windows Docker Deamon and then pull the windowscore image to that one. And then push it to the DTR on the Linux kernel?
If that works than great 
, but isn’t that the same as pulling it from the public Docker Hub?