Startup.cs

public void ConfigureServices(IServiceCollection services) 
{
      services.AddApplicationInsightsTelemetry();

      // Build an intermediate service provider
      var intermediateProvider = services.BuildServiceProvider();

      services.AddGraphQLServer()
              .AddQueryType<QueryType>()
              .AddDiagnosticEventListener<ApplicationInsightsDiagnosticListener>((sp)=> new ApplicationInsightsDiagnosticListener(intermediateProvider.GetService<TelemetryClient>()));
                    
}