Progam 中的代码如下：

public class Program
{
    public static void Main(string[] args)
    {
        CreateHostBuilder(args).Build().Run();
    }

    public static IHostBuilder CreateHostBuilder(string[] args)
    {
        return Host.CreateDefaultBuilder(args)
            .UseSerilog((hostingContext, loggerConfiguration) => loggerConfiguration
                .ReadFrom.Configuration(hostingContext.Configuration))
            .ConfigureWebHost(builer => builer.UseStartup<Startup>());
    }
}

启动时报错

System.InvalidOperationException: Unable to resolve service for type 'Microsoft.AspNetCore.Hosting.Server.IServer' while attempting to activate 'Microsoft.AspNetCore.Hosting.GenericWebHostService'

请问如何解决？