If I comment out my try/catch for the connecting to the API, this is error that I receive is (from line 75 "var postResult = await httpClient.PostAsync(WebAPI, httpContent);"): Newtonsoft.Json.JsonReaderException:
I have used Postman connecting to my web API and put in the JSON string it builds and everything comes back fine. Is there maybe a permission for accessing the internet in iOS that I missed? If so, what permission do I add? I am using Visual Studio 2017 in Windows 10, Newtonsoft.Json version 12.0.1

using System;
using MyApp.Models;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;
using MyApp.Views.DetailViews;
using System.Net.Http;
using System.Net.Http.Headers;
using Newtonsoft.Json;
using System.Collections.Generic;

namespace MyApp.Views
{
    [XamlCompilation(XamlCompilationOptions.Compile)]
    public partial class LoginPage : ContentPage
    {
        private const string WebAPI = "my server address";


        public LoginPage()
        {
                InitializeComponent();
                Init();
        }

        #region Init

        void Init()
        {
            BackgroundColor = Constants.BackgroundColor;
            Lbl_Username.TextColor = Constants.MainTextColor;
            Lbl_Password.TextColor = Constants.MainTextColor;
            ActivitySpinner.IsVisible = false;
            LoginIcon.HeightRequest = Constants.LoginIconHeight;
            App.StartCheckIfInternet(lbl_NoInternet, this);

            Entry_Username.Completed += (object sender, EventArgs e) =>
            {
                Entry_Password.Focus();
            };
            Entry_Password.Completed += (object sender, EventArgs e) =>
            {
                SignInProcAsync(sender,e);
            };
        }
        #endregion

        #region Sign In Procedure
        public async void SignInProcAsync(object sender, EventArgs e)
        {
            try
            {
                //Check for NULL Email and Password
                if (!string.IsNullOrWhiteSpace(Entry_Username.Text) && !string.IsNullOrWhiteSpace(Entry_Password.Text))
                {
                    //Show activity spinner and drop User table, to refresh user data.
                    ActivitySpinner.IsVisible = true;
                    App.UserDatabase.DropTable();

                    //Check user settings
                    if (App.SettingsDatabase.GetSettings() == null)
                    {
                        Settings settings = new Models.Settings();
                        App.SettingsDatabase.SaveSettings(settings);
                    }

                    try
                    {
                        //Connect to API, send JSON file and get post back user JSON file.
                        var httpClient = new HttpClient();
                        var jsonObject = new List<AuthUser>();
                        jsonObject.Add(new AuthUser() { Email = Entry_Username.Text, Password = Entry_Password.Text });
                        string json = JsonConvert.SerializeObject(jsonObject);
                        HttpContent httpContent = new StringContent(json);
                        httpContent.Headers.ContentType = new MediaTypeHeaderValue("application/json");
                        var postResult = await httpClient.PostAsync(WebAPI, httpContent);//Error occurs here only in iOS, UWP and Android works great.
                        var returnJson = await postResult.Content.ReadAsStringAsync();
                        var taskModel = JsonConvert.DeserializeObject<User>(returnJson);
                        App.UserDatabase.AddNewUser(taskModel.Email, taskModel.RoleCode, taskModel.DisplayName, taskModel.AcctNumb, taskModel.DepartmentID, taskModel.UserID);

                        //Check error message
                        if (App.UserDatabase.StatusMessage == 1)
                        {
                            ActivitySpinner.IsVisible = false;
                            await DisplayAlert("Login", "Invalid email and/or password.", "Ok");
                        }
                        else
                        {
                            ActivitySpinner.IsVisible = false;
                            await Navigation.PushModalAsync(new NavigationPage(new HomePage()));
                        }
                    }
                    catch
                    {
                        ActivitySpinner.IsVisible = false;
                        await DisplayAlert("Login", "A error has occurred connecting to server.", "Ok");
                    }



                }
                else
                {
                    ActivitySpinner.IsVisible = false;
                    await DisplayAlert("Login", "Email and/or Password must be entered.", "Ok");
                }
        }
            catch
            {
                ActivitySpinner.IsVisible = false;
                await DisplayAlert("Login", "An error has occurred.", "Ok");
    }

}
        #endregion
    }
}