Problem with .net in game leaderboard with c# challenge

[Sandeep_google]

/usr/share/dotnet/sdk/6.0.301/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.EolTargetFrameworks.targets(28,5): warning NETSDK1138: The target framework 'netcoreapp2.1' is out of support and will not receive security updates in the future. Please refer to https://aka.ms/dotnet-core-support for more information about the support policy. [/home/student_00_94ab0020b2d1/dotnet-docs-samples/applications/demolab/Leaderboard/Leaderboard.csproj]
/usr/share/dotnet/sdk/6.0.301/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.EolTargetFrameworks.targets(28,5): warning NETSDK1138: The target framework 'netcoreapp2.1' is out of support and will not receive security updates in the future. Please refer to https://aka.ms/dotnet-core-support for more information about the support policy. [/home/student_00_94ab0020b2d1/dotnet-docs-samples/applications/demolab/Leaderboard/Leaderboard.csproj]
/home/student_00_94ab0020b2d1/dotnet-docs-samples/applications/demolab/Leaderboard/Leaderboard.csproj : error NU1201: Project CommandLineUtil is not compatible with netcoreapp2.1 (.NETCoreApp,Version=v2.1). Project CommandLineUtil supports: netstandard2.1 (.NETStandard,Version=v2.1)

The build failed. Fix the build errors and run again.

can anybody help me with this ?