Error to connect

[cguanes]

Using the simple example from the documentation

        using (XmppClient client = new XmppClient(hostname, username, password,5222,true))
        {
            // Setup any event handlers.
            // ...
            try { 
            client.Connect();
            }
             catch (Exception ex)
            {
                Debug.WriteLine(  ex.ToString());
            }

}

I'm getting the following error:
Exception thrown: 'System.Globalization.CultureNotFoundException' in mscorlib.dll
System.Globalization.CultureNotFoundException: Culture is not supported.
Parameter name: name
en-US.UTF-8 is an invalid culture identifier.
at System.Globalization.CultureInfo..ctor(String name, Boolean useUserOverride)
at System.Globalization.CultureInfo..ctor(String name)
at S22.Xmpp.Core.StreamParser.ReadRootElement()
at S22.Xmpp.Core.StreamParser..ctor(Stream stream, Boolean leaveOpen)
at S22.Xmpp.Core.XmppCore.InitiateStream(String hostname)
at S22.Xmpp.Core.XmppCore.SetupConnection(String resource)
at S22.Xmpp.Core.XmppCore.Connect(String resource)
at S22.Xmpp.Im.XmppIm.Connect(String resource)
at S22.Xmpp.Client.XmppClient.Connect(String resource)