Unrecognized authentication type

Question

I get this exception

Unhandled Exception: Limilabs.Client.SMTP.SmtpResponseException: Unrecognized authentication type
at Limilabs.Client.SMTP.Smtp.?(String ?, Boolean ?)
at Limilabs.Client.SMTP.Smtp.Login(String user, String password)
at MailProcess.Program.SendMailMessage(String to, String from, String subject, String text, String attachment)
at MailProcess.Program.Main(String[] args)

I think it is caused by our Exchange server but no engineer is able to support me. Can you give me a direction to search for?

Comments

What about this one?

Limilabs.Client.SMTP.SmtpResponseException: Unrecognized authentication type
   at Limilabs.Client.SMTP.Smtp. (String user, String password)
   at Limilabs.Client.SMTP.Smtp.UseBestLogin(String user, String password)
   at EmailReceiver.EmailProcessor.SendMessage(EmailInboxSettings settings, IList`1 recipients, String subject, String body)

Answer 1

Please switch to using UseBestLogin method instead of Login:

using(Smtp smtp = new Smtp())
{
    smtp.Connect("smtp.example.com");  // or ConnectSSL for SSL
    smtp.UseBestLogin("user", "password");
    ....
}