We are required to migrate to a new CDN and will be using new domains going forward," explains Microsoft. "It is possible that azureedge.net domains will have downtime in the near-term.

In a post on Github, Rich Lander, principal program manager, .NET core at Microsoft, offered more detail. “Some .NET binaries and installers are hosted on Azure Content Delivery Network (CDN ...

Due to an unexpected change, .NET users should check immediately whether they are affected. Downtimes may occur.

If it's there, it'll probably need to be changed to the appropriate microsoft.com instance. The new CDN for official builds is builds.dotnet.microsoft.com, and for CI builds, it is ci.dot.net.