Twilio SMS code works from console, but not from ios app

I am writing a business app on IOS and I need to sent preformed text messages when specific events happen. It looked like it would be reasonably easy to do with Twilio, so that is the direction I went down.

I wrote the follow helper in my Forms portable class.

public static class SMSHelper
{
    /*source: http://stackoverflow.com/questions/10077237/httpclient-authentication-header-not-getting-sent 
     * https://www.twilio.com/user/account/developer-tools/api-explorer/message-create
    */
    public static async Task<bool> SendSMS(string to, string msg)
    {
        var url = "https://api.twilio.com/2010-04-01/Accounts/AC{account removed}/Messages.json";
        var rVal = false;
        using (var handler = new HttpClientHandler())
        {
            handler.Credentials = new System.Net.NetworkCredential("AC{Account removed}", "{secret removed}");
            using (var client = new HttpClient(handler))
            {

                var requestContent = new FormUrlEncodedContent(new[] {
            new KeyValuePair<string, string>("To", to),  
            new KeyValuePair<string, string>("From", "(434) 234-4008"),
            new KeyValuePair<string, string>("Body", msg)//System.Net.WebUtility.UrlEncode(msg)),
        });

                HttpResponseMessage response =      client.PostAsync(url,
                                                                       requestContent).Result;
                rVal = response.StatusCode == System.Net.HttpStatusCode.Created || response.StatusCode == System.Net.HttpStatusCode.OK;
                var content = await response.Content.ReadAsStringAsync();
            }
        }


        return rVal;
    }
}

This works great from a testing console app that I wrote. The response is HttpStatusCode.OK and the sms gets sent as expected.

The problem is when I call the same code from within the portable class project (the same one that contains this class) that is used in my Xamarin projects it gets a response statuscode of Unauthorized.

That seems to point to the universal app encoding the handler.Credentials = new System.Net.NetworkCredential("AC{Account removed}", "{secret removed}"); line differently, but I am not really sure where to go from here.

TIA