How to resolve HTTP Web Request underlying connection was closed error calling API?

Question

I am trying to validate the zipCode with City using UPS API "https://www.ups.com/ups.app/xml/AV".

Below is my code

string xmlRequest = "<?xml version=\"1.0\"?>" +
                "<AccessRequest>" +
                "<AccessLicenseNumber>xxxx</AccessLicenseNumber>" +
                "<UserId>xxx</UserId>" +
                "<Password>xxx</Password>" +
                "</AccessRequest>" +
                "<?xml version=\"1.0\"?>" +
                "<AddressValidationRequest xml:lang=\"en-US\">" +
                "<Request>" +
                "<TransactionReference>" +
                "<CustomerContext>Customer Data</CustomerContext>" +
                "<XpciVersion>1.0001</XpciVersion>" +
                "</TransactionReference>" +
                "<RequestAction>AV</RequestAction>" +
                "</Request>" +
                "<Address>" +
                "<PostalCode>" + "38305" + "</PostalCode>" +
                "<City>" + "TENNESSEE" + "</City>" +
                "</Address>" +
                "</AddressValidationRequest>";
                string url = "https://www.ups.com/ups.app/xml/AV";

                ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
                //ServicePointManager.SecurityProtocol = (SecurityProtocolType)3072;
                //ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls11;


                HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
                byte[] requestBytes = System.Text.Encoding.ASCII.GetBytes(xmlRequest);
                req.Method = "POST";
                req.ContentType = "application/x-www-form-urlencode";
                req.ContentLength = requestBytes.Length;
//                req.KeepAlive = false;

                //req.UseDefaultCredentials = true;
  //              req.UserAgent = "Patoooey";
                Stream requestStream = req.GetRequestStream();                
                requestStream.Write(requestBytes, 0, requestBytes.Length);
                requestStream.Close();
                HttpWebResponse res = (HttpWebResponse)req.GetResponse();

                StreamReader sr = new StreamReader(res.GetResponseStream(), System.Text.Encoding.Default);
                string backstr = sr.ReadToEnd();

It works fine on my local machine. but when i deploy it on live server. it gives error The underlying connection was closed: An unexpected error occurred on a receive._____ at System.Net.HttpWebRequest.GetRequestStream(TransportContext& context) at System.Net.HttpWebRequest.GetRequestStream()

I have tried setting ServicePointManager.SecurityProtocol to TLS, TLS11 or TLS12 but nothing is working on live server. Also tried request.KeepAlive = false, request.UseDefaultCredentials = true and request.UserAgent to "any word greater than 5 char".

Server is running Windows Server Data Center SP2 Your help will be appreciated. Thanks

You're sending an XML body with a content type of `application/x-www-form-urlencode`: maybe the server is rejecting your invalid request? — Richard, Jan 30 '18 at 08:41
Just tried the "application/xml" content type. but still the same issue. it is working fine on my local machine. only giving error on server. — mck, Jan 30 '18 at 08:49
did u try this `ServicePointManager.ServerCertificateValidationCallback = (a,b,c,d) => true;` — levent, Jan 30 '18 at 08:53
Tried but nothing changed. if i use the line ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12; then i get the error underlying connection close and if i comment the ServicePointManager.SecurityProtocol then i get the following error The remote server returned an error: (403) Forbidden — mck, Jan 30 '18 at 08:58

score 0 · Answer 1 · answered Sep 04 '18 at 05:53

Even i was facing same issue it was resolved by setting below code ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12; .net picks the highest security protocol by default present in your server
Later for detailed understanding got below reference please refer in case of explanation Default SecurityProtocol in .NET 4.5

How to resolve HTTP Web Request underlying connection was closed error calling API?

1 Answers1