SMTP Stopped Working

The following Code which was working previously suddenly stopped working. Anyone have any idea what's causing it or how to fix it ?

Code (CSharp):

1. using System.Net;
2. using System.Net.Mail;
3. using System.Net.Security;
4. using System.Security.Cryptography.X509Certificates;
5. using System.Text.RegularExpressions;
6.  
7. public void sendMail (string targetEmail, string subject, string content){
8.  
9.      MailMessage mail = new MailMessage();
10.  
11.      mail.From = new MailAddress(acEmail);
12.      mail.To.Add(targetEmail);
13.      mail.Subject = subject;
14.      mail.Body = content;
15.  
16.      SmtpClient smtpServer = new SmtpClient("smtp.gmail.com");
17.      smtpServer.Port = 587;
18.      smtpServer.Credentials = new System.Net.NetworkCredential(acEmail, acPW) as ICredentialsByHost;
19.      smtpServer.EnableSsl = true;
20.      ServicePointManager.ServerCertificateValidationCallback =
21.        delegate(object s, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
22.      { return true; };
23.      smtpServer.Send(mail);
24.      Debug.Log("Email Sent");
25. }

The Error Message shows the following :

 

https://www.google.com/settings/security/lesssecureapps
Check enable and try again

 

hey thanks this much help me

 

Thanks for this!