Невозможно отправить почту от бота, интегрированного с Slack

Question

У меня есть бот, созданный в framework v4 с использованием c#. Бот отправляет электронное письмо администратору, если не может получить ответ от qna maker. Он полностью работает на локальном эмуляторе, я могу отправить письмо, но когда публикуется через слабину, бот выдает ошибку. Вот частный код asyn c Task ProcessSampleQnAAsyn c (WaterfallStepContext stepContext, CancellationToken cancellationToken) {

        var results = await _botServices.SampleQnA.GetAnswersAsync(stepContext.Context);
        if (results.Any())
        {
            await stepContext.Context.SendActivityAsync(MessageFactory.Text(results.First().Answer), cancellationToken);

        }
        else
        {
            var question = stepContext.Context.Activity.Text;
            await stepContext.Context.SendActivityAsync(MessageFactory.Text(_configuration["DefaultAnswer"]), cancellationToken);

            string mailbody = "<h4><b>Hi Admin , following question was not answered from bot :  </b> </h4>" + question;
            Common objCommon = new Common(_configuration);
            objCommon.SendEmail(_configuration["EmailSubject_UnAnswerQuestion"], mailbody);
        }


    }

appsetting. json

"AdminEmailAddress": "****@****.com", //to Email Address
"FromEmailAddress": "******@gmail.com", // From email address
"SMTP_Host": "smtp.gmail.com", // SMTP client Host Name
"SMTP_Port": "587", // SMTP port number
 "SMTP_UserName": "****@gmail.com", // email server user name (Email server 
 network credentials)
 "SMTP_Password": "******", // email server password (Email server network 
credentials)
 "EmailSubject_UnAnswerQuestion": "Question whose answer not found", // 
Subject string for un- answere question email.
"DefaultAnswer": "Sorry, could not find an answer in the Q and A system.", // 
default answere if answere not found in QnA.
 "DelayTimeInSeconds": "60" // Feed back dely time in seconds.

Общий лог c smtp

public class Common
{
    private readonly IConfiguration _configuration;
     public Common(IConfiguration configuration)
{
    _configuration = configuration;
}
public bool SendEmail(string subject, string mailbody)
{
   string to = _configuration["AdminEmailAddress"];   //To address    
    string from = _configuration["FromEmailAddress"];  //From address    
    MailMessage message = new MailMessage(from, to);
    message.Subject = subject;
    message.Body = mailbody;
    message.BodyEncoding = Encoding.UTF8;
    message.IsBodyHtml = true;
    SmtpClient client = new SmtpClient(_configuration["SMTP_Host"], 
  int.Parse(_configuration["SMTP_Port"])); //Gmail smtp    
    System.Net.NetworkCredential basicCredential1 = new
    System.Net.NetworkCredential(_configuration["SMTP_UserName"], 
   _configuration["SMTP_Password"]);
    client.EnableSsl = true;
    client.UseDefaultCredentials = false;
    client.Credentials = basicCredential1;
    try
    {
        client.Send(message);
        return true;
    }catch (Exception ex)
    {
        throw ex;
    }}