This error indicates that the .NET SDK is not installed or not properly configured. To fix:

Install .NET SDK: Download and install the latest .NET SDK from Microsoft's .NET Download page. Verify Installation: Run dotnet --info in the command prompt to ensure the SDK is installed and recognized. Check Environment Variables: Ensure the PATH environment variable includes the .NET SDK path, typically C:\Program Files\dotnet. Retry the Command: Run the restore and publish commands again.