For those that are still interested, I did finally manage to get this to work on Proget 2025.8. This is what I had to do. First, you need to create your own certificate template based off the default Web Server template, and make sure you can export the private keys, and most importantly add Client Authentication to the template as it will not work if you don't. I also added the computer name account on the security tab to be able to "Enroll" the certificate. On my issuing certificate authority, I went into Certification Authority MMC, and under "Certificate Templates" right click and under New- Certificate template to issue. After adding the template you just created, go to the windows server you are running this under and open up certlm.msc. Under Personal- Certificates right click "Request New Certificate". Find your certificate you created under the AD Enrollment Policy. Add subject name, and make sure to add the netbios name and fqdn under dns. Give it a subject name like Proget or something else to make it stand out. You should be able to accept the rest of the defaults. Make sure the "Client Authentication" is with "Server Authentication" or it won't work. After that is done, right click your new certificate All Tasks-Manage Private Keys and add "Network Service" and give it full control. After that, your certificate is ready. In ProGet, add the certificate from the computer personal store under "My" and after that, you should be able to access it under https://server.domain.local:8625. You should be in and should have a secure connection at that point.