The issue has been resolved for now. I’m able to build on our pipeline again.
The Azure pipeline uses the NuGet.config file provided in our project, which only includes api.nuget.org and nuget.abp.io. This issue starts to occur after midday. On my local development machine, when I try to list nuget.abp.io packages, the IDE asks for a username and password.
We are also experiencing the same issue. Our pipeline cannot restore the Volo.* packages, even though I provided the correct key. I tried your solution, but unfortunately, it did not resolve the problem.