getting error The underlying connection was closed: The connection was closed unexpectedly

Dear All,

Here i am using below code to request a url as web request.

try

{

HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);

HttpWebResponse resp = (HttpWebResponse)req.GetResponse();

Stream st = resp.GetResponseStream();

StreamReader sr = new StreamReader(st);

string buffer = sr.ReadToEnd();

sr.Close();

st.Close();

}

catch (Exception Ex)

{

Response.Write(Ex.Message);

}

when i run the above code in my button press event its giving below error,

The underlying connection was closed: The connection was closed unexpectedly

Please help me out.

I also spoke with my sms API provider. there is no problem from their side.