Newtonsoft.Json.JsonReaderException: Unexpected character encountered while parsing value: E

This is the sample code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using Dropbox.Api;
using Dropbox.Api.Team;

namespace DropBoxConnectorSample
{
    internal class Program
    {
        private sealed class CustomWebRequestHandler : WebRequestHandler
        {
            protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request,
                CancellationToken cancellationToken)
            {
                var requestBody = await request.Content.ReadAsStringAsync();
                Console.WriteLine(">>> " + requestBody);

                var result = await base.SendAsync(request, cancellationToken);

                var resultBody = await result.Content.ReadAsStringAsync();
                Console.WriteLine("<<< " + resultBody);

                return result;
            }
        }

        private HttpClient CreateHttpClient()
        {
            var handler = new CustomWebRequestHandler
            {
                ReadWriteTimeout = 10 * 1000
            };
            if (handler.SupportsAutomaticDecompression)
                handler.AutomaticDecompression = DecompressionMethods.Deflate
                                                 | DecompressionMethods.GZip;

            return new HttpClient(handler) { Timeout = TimeSpan.FromHours(24) };
        }

        private DropboxTeamClient CreateTeamClientAsync()
        {
            var httpClient = CreateHttpClient();
            const int retryCount = 4;
            return new DropboxTeamClient("YOUR TOKEN",
                new DropboxClientConfig(null, retryCount) { HttpClient = httpClient });
        }

        private async Task<string> FindMemberIdAsync(DropboxTeamClient client)
        {
            var criterium = new UserSelectorArg.Email("YOUR EMAIL");
            var memberInfo = await client.Team.MembersGetInfoAsync(new[] { criterium }).ConfigureAwait(false);
            var id = memberInfo.FirstOrDefault()?.AsMemberInfo?.Value?.Profile?.TeamMemberId;
            if (id == null) throw new InvalidOperationException("Could not find a dropbox user.");

            return id;
        }

        private async Task<DropboxClient> CreateClientAsync()
        {
            var teamClient = CreateTeamClientAsync();
            var memberId = await FindMemberIdAsync(teamClient).ConfigureAwait(false);
            return teamClient.AsMember(memberId);
        }

        public async Task<IEnumerable<string>> ListFoldersAsync(string relativePath)
        {
            var client = await CreateClientAsync().ConfigureAwait(false);

            var folders = await client.Files.ListFolderAsync(relativePath).ConfigureAwait(false);
            var result = folders.Entries.Where(e => e.IsFolder).Select(e => e.AsFolder.Name).ToList();
            while (folders.HasMore)
            {
                folders = await client.Files.ListFolderContinueAsync(folders.Cursor).ConfigureAwait(false);
                result.AddRange(folders.Entries.Where(e => e.IsFolder).Select(e => e.AsFolder.Name));
            }

            return result;
        }

        private static async Task Main(string[] args)
        {
            while (true)
            {
                var p = new Program();
                var result = await p.ListFoldersAsync("/Test");
                Console.WriteLine("END: " + string.Join(", ", result));
            }
        }
    }
}

As you can see I have managed to dump the actual communication with DropBox servers.