How come I can't see my organization (which I am owner of) ?
My guess was that it was due to some early-stage preview issues, so I have been postponing this post for a while, but now I am too curious, so I would like to know if anyone else has succeeded connecting a repository. :)
Found a solution. Press the "Click here and enter your repository URL manually"
You have to be aware that you can't just copy in your URL from the repository. You need to follow the exact syntax provided as greyed out text in the text-box. This includes a '/MyTestOrg/' inside the URL, which is not present if you just copy the URL from the DevOps repositories page.