That was the answer. Something about the API key was not working. I had to delete the source and recreate but that still didn't fix it. I then had to go into OSS side and regenerate the API key and add it back to the newly created source. Thanks again for pointing me in the right direction.

When running a vulnerability scan on the unapproved nuget feed I get the following error.

"Padding is invalid and cannot be removed."

There is no additional information that I can find. I did see a similar post in this forum here but no resolution was offered. Has anyone had this problem on Proget?