WCF ERROR: The server did not provide a meaningful reply; - wcf

Question

please somebody can help me to find out what is happened. I have my WCF service which worked fine, and now suddenly I have this error:
The server did not provide a meaningful reply; this might be caused by a contract mismatch, a premature session shutdown or an internal
server error
I must tell that it still works when I select some thousands of records, but when the data is huge I receive this error, although before it worked fine!
private static string ConnString = "Server=127.0.0.1; Port=5432; Database=DBname; User Id=UName; Password=MyPassword;"
DataTable myDT = new DataTable();
NpgsqlConnection myAccessConn = new NpgsqlConnection(ConnString);
myAccessConn.Open();
string query = "SELECT * FROM Twitter";
NpgsqlDataAdapter myDataAdapter = new NpgsqlDataAdapter(query, myAccessConn);
myDataAdapter.Fill(myDT);
foreach (DataRow dr in myDT.Rows)
{
**WHEN I HAVE TOO MANY RECORDS IT STOPS HERE**
...
web.config
<configuration>
<system.web>
<compilation debug="false" targetFramework="4.0" />
<httpRuntime maxRequestLength="2147483647" executionTimeout="100000" />
</system.web>
<system.diagnostics>
<trace autoflush="true" />
<sources>
<source name="System.ServiceModel"
switchValue="Information, ActivityTracing"
propagateActivity="true">
<listeners>
<add name="traceListener" type="System.Diagnostics.XmlWriterTraceListener" initializeData="Traces4.svclog"/>
</listeners>
</source>
</sources>
</system.diagnostics>
<system.serviceModel>
<bindings>
<basicHttpBinding>
<binding name="BasicHttpBinding_IDBService" closeTimeout="00:30:00"
openTimeout="00:30:00" receiveTimeout="00:30:00" sendTimeout="00:30:00"
allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard"
maxBufferSize="2147483647" maxBufferPoolSize="2147483647" maxReceivedMessageSize="2147483647"
messageEncoding="Text" textEncoding="utf-8" transferMode="Streamed"
useDefaultWebProxy="true">
<readerQuotas maxDepth="2147483647" maxStringContentLength="2147483647" maxArrayLength="2147483647"
maxBytesPerRead="2147483647" maxNameTableCharCount="2147483647" />
<security mode="None">
<transport clientCredentialType="None" proxyCredentialType="None"
realm="" />
<message clientCredentialType="UserName" algorithmSuite="Default" />
</security>
</binding>
</basicHttpBinding>
</bindings>
<client>
<endpoint address="" binding="basicHttpBinding"
bindingConfiguration="BasicHttpBinding_IDBService" contract="DBServiceReference.IDBService"
name="BasicHttpBinding_IDBService" />
</client>
<behaviors>
<serviceBehaviors>
<behavior name="">
<serviceMetadata httpGetEnabled="true" />
<serviceDebug includeExceptionDetailInFaults="true" />
<dataContractSerializer maxItemsInObjectGraph="2147483646" />
</behavior>
</serviceBehaviors>
</behaviors>
<serviceHostingEnvironment aspNetCompatibilityEnabled="false" multipleSiteBindingsEnabled="true" />
</system.serviceModel>
</configuration>
client config (Edited)
<configuration>
<system.serviceModel>
<bindings>
<basicHttpBinding>
<binding name="BasicHttpBinding_IRouteService" maxBufferSize="2147483647"
maxReceivedMessageSize="2147483647">
<security mode="None" />
</binding>
<binding name="BasicHttpBinding_IDBService" closeTimeout="00:30:00"
openTimeout="00:30:00" receiveTimeout="00:30:00" sendTimeout="00:30:00"
maxBufferSize="2147483647" maxReceivedMessageSize="2147483647"
transferMode="Buffered" >
<security mode="None" />
</binding>
</basicHttpBinding>
<customBinding>
<binding name="CustomBinding_IRouteService">
<binaryMessageEncoding />
<httpTransport maxReceivedMessageSize="2147483647"
maxBufferSize="2147483647" />
</binding>
</customBinding>
</bindings>
<client>
<endpoint address="http://dev.virtualearth.net/webservices/v1/routeservice/routeservice.svc"
binding="basicHttpBinding" bindingConfiguration="BasicHttpBinding_IRouteService"
contract="BingRoutingService.IRouteService" name="BasicHttpBinding_IRouteService" />
<endpoint address="http://dev.virtualearth.net/webservices/v1/routeservice/routeservice.svc/binaryHttp"
binding="customBinding" bindingConfiguration="CustomBinding_IRouteService"
contract="BingRoutingService.IRouteService" name="CustomBinding_IRouteService" />
<endpoint address="" binding="basicHttpBinding" bindingConfiguration="BasicHttpBinding_IDBService"
contract="DBServiceReference.IDBService" name="BasicHttpBinding_IDBService" />
</client>
</system.serviceModel>
</configuration>
In my file scvlog I don' t get any exception!
I don't have any other idea what else I can do for understand where is the problem. Please somebody help me!!!

Answer 1

A different answer, just in case anyone arrives here as I did looking for a general answer to the question.
It seems that the DataContractSerializer that does the donkey-work is incredibly finicky, but doesn't always pass the real error to the client. The server process dies straight after the failure - hence no error can be found. In my case the problem was an enum that was used as flags, but not decorated with the [Flags] attribute (picky or what!).
To solve it I created an instance of the serializer and inspected the error in the debugger; here's a code snippet since I have it to hand.
EDIT: In response to request in comments ...
Amended the code snippet to show the helper method I now use. Much the same as before, but in a handy generic wrapper.
public static T CheckCanSerialize<T>(this T returnValue) {
var lDCS = new System.Runtime.Serialization.DataContractSerializer(typeof(T));
Byte[] lBytes;
using (var lMem1 = new IO.MemoryStream()) {
lDCS.WriteObject(lMem1, returnValue);
lBytes = lMem1.ToArray();
}
T lResult;
using (var lMem2 = new IO.MemoryStream(lBytes)) {
lResult = (T)lDCS.ReadObject(lMem2);
}
return lResult;
}
And to use this, instead of returning an object, return the object after calling the helper method, so
public MyDodgyObject MyService() {
... do lots of work ...
return myResult;
}
becomes
public MyDodgyObject MyService() {
... do lots of work ...
return CheckCanSerialize(myResult);
}
Any errors in serialization are then thrown before the service stops paying attention, and so can be analysed in the debugger.
Note; I wouldn't recommend leaving the call in production code, it has the overhead of serializing and deserializing the object, without any real benefit once the code is debugged.
Hope this helps someone - I've wasted about 3 hours trying to track it down.

Answer 2

I don't know if it's really can be an answer, but I have tried to change in web.config from <security mode="None" /> to <security mode="Transport" /> and It worked!!!
I'd want to pay attention that this part should be changed only in web.config and in client configuration remains <security mode="None" />, because with Transport in both It doesn't work!
So after that, I decided to try to come back again to None security and It worked for some minutes and then stopped again, and it came back the error:
The server did not provide a meaningful reply; this might be caused by a contract mismatch, a premature session shutdown or an internal server error
So It seems that the solution in my case is to set in web.config
security mode to Transport

Answer 3

In my case, I was working on a windows app project communicating with a WCF Web Service.
The web service, using netTcpBinding was returning a Stream object (a picture).
As the windows app doesn't have configuration file, default values are used for bindings. And simply extending the MaxReceivedMessageSize on the client side backend code solved my problem.
var API = new StreamService.StreamServiceClient(
new System.ServiceModel.NetTcpBinding(System.ServiceModel.SecurityMode.None)
{
MaxReceivedMessageSize = 2147483647
},
new System.ServiceModel.EndpointAddress("net.tcp://machine/app/service.svc")
);

Answer 4

Sometimes this problem is caused by an oversized message that was cut due to default values in the binding.
You should add maxReceivedMessageSize, maxBufferPoolSize and maxBufferSize with some large enough values to the binding in your app.config file - that should do the trick :)
Example:
<bindings>
<netTcpBinding>
<binding
name="ExampleBinding" closeTimeout="00:01:00"
maxReceivedMessageSize="73400320"
maxBufferPoolSize="70000000"
maxBufferSize="70000000"/>
</netTcpBinding>
</bindings>
Good Luck!

Answer 5

In my case I was working on an MVC application and I have changed
maxReceivedMessageSize ="10000000"
to
maxReceivedMessageSize ="70000000"
and it worked! It's because the response from the web server exceeds maxReceivedMessageSize ="10000000",
so I have increased maxReceivedMessageSize to maxReceivedMessageSize ="70000000".

Answer 6

In my experience of this error, just check the service's host computer's event log to see what is the actual root exception.

Answer 7

For me it was a lazy-loading list of items retrieved from the DB.
The WCF receiver would try to iterate them, which would try to go to the DB, which obviously could not work.

Answer 8

In BizTalk we use to get this issue.
Mostly the issue will happen due to size of the message from the service. So we need to increase the size of the receiving message from 65,356 to 2,365,60. It worked for me.
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Answer 9

ASP.NET applications can execute with the Windows identity (user account) of the user making the request. Impersonation is commonly used in applications that rely on Microsoft Internet Information Services (IIS) to authenticate the user. ASP.NET impersonation is disabled by default.
Enable this, your API will start working - it is in IIS authentication

Answer 10

In my case, after upgrading from .NET Framework 4.5 to .NET Framework 4.8, I had to remove read-only modifiers of properties that were decorated with DataMemberAttribute.