NuGet Unable to load the service index for source Authentication failed

Question

Since today for some reason I'm unable to connect to the NuGet package manager through Visual Studio.

[nuget.org] Unable to load the service index for source https://api.nuget.org/v3/index.json.
  An error occurred while sending the request.
  The underlying connection was closed: An unexpected error occurred on a send.
  Authentication failed because the remote party has closed the transport stream.

But I cannot get it to work again... Things I tried.

• Delete NuGet.config
• Clear NuGet cache
• Disable TLS1.0 and TLS1.1 explicitly
• Enabled TLS1.2 explicitly
• followed the manual from nuget at https://devblogs.microsoft.com/nuget/deprecating-tls-1-0-and-1-1-on-nuget-org/
• Different Visual Studios
• Update to the latest Visual Studio 2019
• Tried different TLS settings in the RegEdit for 1.0, 1.1 and 1.2. I don't have a TLS1.3 section yet.
• I can browse to https://api.nuget.org/v3/index.json with chrome

TLS1.2 Client settings:

TLS1.2 Server settings:

Specs: Windows Server 2012R2, Visual Studio 2019

Also tried it on a different Windows Server 2012R2 machine and same problem

It is still working on my laptop with Windows 10.

Hopefully someone has an idea.

Thanks

Answer 1

Had exactly the same problem, running script from https://github.com/microsoft/azure-devops-tls12 and following instructions from it helped me. In my case it generated additional script file, after running that and restaring pc nuget was working once again.