Help!A connection attempt failed because the connected party did not properly respond

This website was working for ages until recently though I have myself not made any changes.
The website is hosted with Fasthosts and it's domain is registered with 123-reg.

Whenever I try and talk to a webservice it now throws the below error message back. I've contacted Fasthosts and they think I've changed the code because they think it's wrong and 123-reg have no idea.
The webservice is used on other websites I have and they are working fine, it's only this one.

Help!

Code:

A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 81.31.115.21:443
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.Net.Sockets.SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 81.31.115.21:443

Source Error: 

Line 198:        ServicePointManager.ServerCertificateValidationCallback = ((sender, certificate, chain, sslPolicyErrors) => true);
Line 199:
Line 200:        System.Net.HttpWebResponse wr = (System.Net.HttpWebResponse)wreq.GetResponse();
Line 201:        //read xml stream
Line 202:        if (wr.StatusCode == System.Net.HttpStatusCode.OK)

Source File: e:\DOMAINS\m\mynlalandlord.org.uk\user\htdocs\test1.aspx.cs    Line: 200 

Stack Trace: 

[SocketException (0x274c): A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 81.31.115.21:443]
   System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress) +239
   System.Net.Sockets.Socket.InternalConnect(EndPoint remoteEP) +35
   System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Int32 timeout, Exception& exception) +224

[WebException: Unable to connect to the remote server]
   System.Net.HttpWebRequest.GetResponse() +5314029
   Default2.getSSL(String MemNo) in e:\DOMAINS\m\mynlalandlord.org.uk\user\htdocs\test1.aspx.cs:200
   Default2.btnValidate(Object sender, EventArgs e) in e:\DOMAINS\m\mynlalandlord.org.uk\user\htdocs\test1.aspx.cs:52
   System.Web.UI.WebControls.ImageButton.OnClick(ImageClickEventArgs e) +108
   System.Web.UI.WebControls.ImageButton.RaisePostBackEvent(String eventArgument) +118
   System.Web.UI.WebControls.ImageButton.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13
   System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1565

This is the class that the code errors on:

Code:

public static XmlDocument getSSL(string MemNo)
    {
        //retrieve XML document from Rest server for Stratum details
        string url;
        url = "https://81.31.115.21/";
        string result = "Error communicating with server";
        XmlDocument xmlDoc = new System.Xml.XmlDocument();

        //allows for validation of SSL certificates 
        [COLOR="DarkOrange"][B]System.Net.HttpWebRequest wreq = (System.Net.HttpWebRequest)System.Net.WebRequest.Create(url);[/B][/COLOR]
        wreq.Proxy = null;
        wreq.Credentials = CredentialCache.DefaultCredentials;
        wreq.Method = "GET";
        //wreq.Timeout = 10000;

        //ignore all certificate errors
        ServicePointManager.ServerCertificateValidationCallback = ((sender, certificate, chain, sslPolicyErrors) => true);

        System.Net.HttpWebResponse wr = (System.Net.HttpWebResponse)wreq.GetResponse();
        //read xml stream
        if (wr.StatusCode == System.Net.HttpStatusCode.OK)
        {
            System.IO.Stream s = wr.GetResponseStream();
            System.Text.Encoding enc = System.Text.Encoding.GetEncoding("utf-8");
            System.IO.StreamReader readStream = new System.IO.StreamReader(s, enc);
            result = readStream.ReadToEnd();
            xmlDoc.LoadXml(result);
            readStream.Close();
        }
        wr.Close();
        return xmlDoc;
    }