C# 多次刷新后从服务器获取服务器错误503

我在asp.net应用程序中通过通配符设置了子域。子域路由工作得很完美，但由于某些原因，如果我快速刷新页面两次，就会出现以下错误：

The remote server returned an error: (503) Server Unavailable.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.Net.WebException: The remote server returned an error: (503) Server Unavailable.

堆栈跟踪：

[WebException: The remote server returned an error: (503) Server Unavailable.]
   System.Net.WebClient.DownloadDataInternal(Uri address, WebRequest& request) +365
   System.Net.WebClient.DownloadString(Uri address) +111
   WebApplication3.Controllers.OtherController.Dynamic(String someValue, String Id) +2168
   lambda_method(Closure , ControllerBase , Object[] ) +191
   System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +229
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +35
   System.Web.Mvc.Async.AsyncControllerActionInvoker.<BeginInvokeSynchronousActionMethod>b__39(IAsyncResult asyncResult, ActionInvocation innerInvokeState) +39
   System.Web.Mvc.Async.WrappedAsyncResult`2.CallEndDelegate(IAsyncResult asyncResult) +77
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +69
   System.Web.Mvc.Async.AsyncInvocationWithFilters.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3d() +72
   System.Web.Mvc.Async.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f() +387
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) +42
   System.Web.Mvc.Async.<>c__DisplayClass2b.<BeginInvokeAction>b__1c() +38
   System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) +188
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +38
   System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +29
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +73
   System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +52
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +39
   System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +38
   System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +43
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +73
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +38
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +602
   System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +195
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +128

这个问题背后的原因可能是什么？有人能帮我吗

我试图访问的子域是：

http://subdomain.example.com/routeIdParameter

---

api无法访问已安装的服务器a

如果您能提供一个api，以便我们可以看到正在执行的控制器操作，那就太棒了。这是什么意思？如果我不刷新太多次，我可以正常到达它。。。。

http://subdomain.example.com/routeIdParameter