ClientLibraryConsoleAppSample doesn't run as netcoreapp2.0 or net5.0

I'm developing a .Net 5 Console App to automate some actions on Azure DevOps WorkItems.

As my authorization isn't working I started ClientLibraryConsoleAppSample to get a hint was is wrong.

The current version is running as net452 and all is working but when I change the TargetFramework to netcoreapp2.0 or to net5.0 I get an error:

Unhandled Exception: System.AggregateException: One or more errors occurred. (VS30063: You are not authorized to access https://dev.azure.com.) ---> Microsoft.VisualStudio.Services.Common.VssUnauthorizedException: VS30063: You are not authorized to access https://dev.azure.com.
   at Microsoft.VisualStudio.Services.Common.VssHttpMessageHandler.<SendAsync>d__17.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.Services.Common.VssHttpRetryMessageHandler.<SendAsync>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1.ConfiguredTaskAwaiter.GetResult()
   at System.Net.Http.HttpClient.<FinishSendAsyncBuffered>d__58.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.Services.WebApi.VssHttpClientBase.<SendAsync>d__51.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.Services.WebApi.VssHttpClientBase.<SendAsync>d__47`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.Services.WebApi.VssHttpClientBase.<SendAsync>d__28`1.MoveNext()
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
   at ClientLibraryConsoleAppSample.Program.Main(String[] args) in d:\Repos\vsts-auth-samples\ClientLibraryConsoleAppSample\Program.cs:line 27

C:\Program Files\dotnet\dotnet.exe (process 67652) exited with code -532462766.

Start with ClientLibraryConsoleAppSample/Program.cs at line 27 and compare the sample's behavior under net452, netcoreapp2.0, and net5.0. Verify the authorization setup and target-framework behavior; done when the sample runs successfully against Azure DevOps without VS30063.