The underlying connection was closed: An unexpected error

Question

Hi,

We are getting error message when connecting to Smater Mail API

Inner Exception: {"Unable to read data from the transport connection: An
existing connection was forcibly closed by the remote host."}

Message: The underlying connection was closed: An unexpected error occurred
on a send.

How to slove this issue?

sumesh np · Answer

Here is the code i am using private void Invoke(string methodName, bool encode) { AssertCanInvoke(methodName); string soapStr = @" xmlns:xsd=""http://www.w3.org/2001/XMLSchema"" xmlns:soap=""http://schemas.xmlsoap.org/soap/envelope/""> {1} "; HttpWebRequest req = (HttpWebRequest)WebRequest.Create(Url); req.Headers.Add("SOAPAction", "\"http://tempuri.org/" + methodName + "\""); req.ContentType = "text/xml;charset=\"utf-8\""; //req.Accept = "text/xml"; req.Accept = "text/xml"; req.Method = "POST"; //req.Accept = "*/*"; //req.UserAgent = "MyApp"; req.KeepAlive = false; using (Stream stm = req.GetRequestStream()) { string postValues = ""; foreach (var param in Params) { if (encode) postValues += string.Format(" {1} ", HttpUtility.HtmlEncode(param.Key), HttpUtility.HtmlEncode(param.Value)); else postValues += string.Format(" {1} ", param.Key, param.Value); } soapStr = string.Format(soapStr, methodName, postValues); using (StreamWriter stmw = new StreamWriter(stm)) { stmw.Write(soapStr); } } using (StreamReader responseReader = new StreamReader(req.GetResponse().GetResponseStream())) { string result = responseReader.ReadToEnd(); ResponseSOAP = XDocument.Parse(Utils.UnescapeString(result)); ExtractResult(methodName); } }

Mukil Vendhan · Answer

The underlying connection was closed: An unexpected error occurred on a receive. This problem occurs when the server or another network device unexpectedly closes an existing Transmission Control Protocol (TCP) connection. This problem may occur when a time-out value on the server or on the network device is set too low. To resolve this problem, see resolutions A, D, E, F, and O. The problem can also occur if the server resets the connection unexpectedly, such as if an unhandled exception crashes the server process. Analyze the server logs to see if this may be the issue. Resolution To resolve this problem, make sure that you are using the most recent version of the .NET Framework. Add a method to the class to override the GetWebRequest method. This change lets you access the HttpWebRequest object. If you are using Microsoft Visual C#, the new method must be similar to the following. class MyTestService : TestService . TestService { protected override WebRequest GetWebRequest ( Uri uri ) { HttpWebRequest webRequest = ( HttpWebRequest ) base . GetWebRequest ( uri ); //Setting KeepAlive to false webRequest . KeepAlive = false ; return webRequest ; } } Excerpt from KB915599: You receive one or more error messages when you try to make an HTTP request in an application that is built on the .NET Framework 1.1 Service Pack 1.