WCF hosted in Azure throws System.Net.WebException when client tries to connect RRS feed

  • Question

  • I have a weird problem. Every few weeks, my WCF Web Servie hosted in Azure will throws System.Net.WebException: The remote server returned an error: (500) Internal Server Error.

    Once that happen, I am no longer able to connect to the service. None of the connection will work until I am physically login to Azure portal and restart (stop/start) Azure Cloud Services.

    Recently, I am able to replicate this problem in my local computer during debugging. At one instance, I was debugging a code and I left a debug break point too long (about 15 minutes). I get the following error (on client side) when I tried to connect:

    System.ServiceModel.ProtocolException: The content type text/html; charset=utf-8 of the response message does not match the content type of the binding (application/soap+xml; charset=utf-8). If using a custom encoder, be sure that the IsContentTypeSupported method is implemented properly. The first 1024 bytes of the response were: '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "">
    <html xmlns="">
    <title>IIS 10.0 Detailed Error - 500.19 - Internal Server Error</title>
    <style type="text/css">
    .config_source code{font-size:.8em;color:#000000;}
    ul,ol{margin:10px 0 10px 5px;}
    fieldset{padding:0 15px 10px 15px;word-break:break-all;}
    .summary-container fieldset{padding-bottom:5px;margin-top:4px;}{padding:2px 15px 4px 10px;margin:0 0 0 -12px;}
    legend{color:#333333;;margin:4px 0 8px -12px;_margin-top:0px;
    h2{font-size:1.7em;margin:'. ---> System.Net.WebException: The remote server returned an error: (500) Internal Server Error.
       at System.Net.HttpWebRequest.GetResponse()
       at System.ServiceModel.Channels.HttpChannelFactory`1.HttpRequestChannel.HttpChannelRequest.WaitForReply(TimeSpan timeout)
       --- End of inner exception stack trace ---
    Server stack trace:
       at System.ServiceModel.Channels.HttpChannelUtilities.ValidateRequestReplyResponse(HttpWebRequest request, HttpWebResponse response, HttpChannelFactory`1 factory, WebException responseException, ChannelBinding channelBinding)
       at System.ServiceModel.Channels.HttpChannelFactory`1.HttpRequestChannel.HttpChannelRequest.WaitForReply(TimeSpan timeout)
       at System.ServiceModel.Channels.RequestChannel.Request(Message message, TimeSpan timeout)
       at System.ServiceModel.Channels.SecurityChannelFactory`1.SecurityRequestChannel.Request(Message message, TimeSpan timeout)
       at System.ServiceModel.Security.SecuritySessionSecurityTokenProvider.DoOperation(SecuritySessionOperation operation, EndpointAddress target, Uri via, SecurityToken currentToken, TimeSpan timeout)
       at System.ServiceModel.Security.SecuritySessionSecurityTokenProvider.GetTokenCore(TimeSpan timeout)
       at System.IdentityModel.Selectors.SecurityTokenProvider.GetToken(TimeSpan timeout)
       at System.ServiceModel.Security.SecuritySessionClientSettings`1.ClientSecuritySessionChannel.OnOpen(TimeSpan timeout)
       at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)
       at System.ServiceModel.Channels.ServiceChannel.OnOpen(TimeSpan timeout)
       at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)
    Exception rethrown at [0]:
       at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
       at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
       at System.ServiceModel.ICommunicationObject.Open(TimeSpan timeout)
       at System.ServiceModel.ClientBase`1.System.ServiceModel.ICommunicationObject.Open(TimeSpan timeout)
       at System.ServiceModel.ClientBase`1.Open()
       at WMShared.WMWeb.Login(String username, String password) in C:\PRO\WarehouseManagement\Libraries\WMShared\WMAPIWeb.cs:line 54
       at WMShared.WMWeb.WebReq.Login(String username, String password, XRestServiceClient& xrsClient) in C:\PRO\WarehouseManagement\Libraries\WMShared\Services\WebReq\WebReq.cs:line 100

    It looks like the WCF server is unable to recover?

    In the server, I also get an exception when I tried to start a background worker using Task.Factory.StartNew():

    System.Threading.Tasks.TaskSchedulerException: 'An exception was thrown by a TaskScheduler.'
    Inner Exception
    AppDomainUnloadedException: Attempted to access an unloaded AppDomain.

    When I tried to view the service using https://localhost:44300/WarehouseManagementService.svc I get this error:

    Detailed Error Information:
        Module     CustomErrorModule
        Notification       SendResponse
        Handler    Not yet determined
        Error Code     0x80070490
        Config Error       The configuration section 'system.webServer/httpErrors' cannot be read because it is missing a section declaration
        Config File    \\?\C:\Users\shopkins\AppData\Local\dftmp\Resources\aa0cf43d-1904-4c6d-a283-0c6c75c83825\temp\temp\RoleTemp\applicationHost.config

    I am keep getting those error until I physically restart the service.

    Any idea how to recover or restart WCF service again?


    Saturday, February 17, 2018 12:42 PM

All replies

  • It's just a 500 error and not a 500.xx?
    Saturday, February 17, 2018 9:29 PM
  • Hi SamOutlook,

    >>At one instance, I was debugging a code and I left a debug break point too long (about 15 minutes)

    For this error, it seems to be related with timeout error, I suggest you increase Timeout Settings in service side.

          <binding name="longTimeoutBinding"
            receiveTimeout="00:10:00" sendTimeout="00:10:00">
            <security mode="None"/>
        <service name="longTimeoutService"
          <endpoint address="net.tcp://localhost/longtimeout/"
            binding="netTcpBinding" bindingConfiguration="longTimeoutBinding" />

    To check the depth error message, I would suggest you enable includeExceptionDetailInFaults as true.

            <behavior name="My">
              <!-- To avoid disclosing metadata information, set the values below to false before deployment -->
              <serviceMetadata httpGetEnabled="true" httpsGetEnabled="true"/>
              <!-- To receive exception details in faults for debugging purposes, set the value below to true.  Set to false before deployment to avoid disclosing exception information -->
              <serviceDebug includeExceptionDetailInFaults="true"/>

    In addition, I suggest you enable WCF Tracing.

    Best Regards,

    Tao Zhou

    MSDN Community Support
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    Monday, February 19, 2018 12:49 PM