Hi @Andrei_Epure,
it had nothing to do with the type of my projects. My projects were recognized as test-projects. That was the problem.
I found this line in my logs:
INFO: Found 4 MSBuild C# projects: 1 MAIN project. 3 TEST projects.
I added this to my *.csproj files:
<PropertyGroup>
<SonarQubeTestProject>false</SonarQubeTestProject>
</PropertyGroup>
Now it works.
Found the solution here:
Problem with C# project analysis - Get help / SonarCloud - SonarSource Community
Thanks
Daniel