The request was aborted: Could not create SSL/TLS secure channel C# SPML

Question

All,

I am completely new to SPML or webserivces. I know there a lot of questions regarding this issue. I have tried everything I could find. But, I guess my issues is not knowing how to format the request.

  protected void Page_Load(object sender, EventArgs e)
    {

        AddRequestType addreq = new AddRequestType();
        addreq.executionMode = ExecutionModeType.asynchronous;
        addreq.returnData = ReturnDataType.identifier;
        identity ident = new identity();
        ident.username = new string[] { "jsmith" };

        X509Store store = new X509Store(StoreName.TrustedPublisher, StoreLocation.LocalMachine);
        store.Open(OpenFlags.ReadOnly);
        var cert = store.Certificates;

        ServicePointManager.Expect100Continue = true;
        ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls11;

        SPMLService client = new SPMLService();
        client.UseDefaultCredentials = true;

        var res = client.SPMLAddRequest(addreq);

        AddResponseType addresp = new AddResponseType();
        //addresp.requestID={ requestID};
        var status = addresp.status;
        var error = addresp.error;
        var error_msg = addresp.errorMessage;
    }

I have a certificate on the computer and I am able to read the certificate. Any guidance on how to create a SMPL request is greatly appreciated.