AddHealthCheck.cs

public void ConfigureServices(IServiceCollection services)
{            
    services.AddDbContext<PeriodContext>(options =>
        options.UseSqlServer(
            Configuration.GetConnectionString("DbConnectionString"),
            builderOptions =>
                builderOptions.EnableRetryOnFailure(3)),
        ServiceLifetime.Scoped);

    services.AddHealthChecks()
        .AddCheck("SQL Server",
        new DatabaseHealthCheck(
            services.BuildServiceProvider()
            .GetService<PeriodContext>()));

	  // rest of the services
}