Ask HN: How to complete registartion as a Microsoft partner?

I'm trying to register as a Microsoft partner so I can verify my windows desktop app and not show users the "the app is trying to light your computer ablaze" messages on startup, and after registering via https://partner.microsoft.com/en-US/ they made a special email @onmicrosoft.com that just loops back to login when I try to use it!

Has anyone sucessfully done this process? Is it even still used?