Exchange 2013 authentication problem with SMTP

Question

Hello,

we installed your mail.dll on clients location, client has Exchange 2013 server and receive mail is functional, i can see the e-mails. Problem is when i try to send e-mail, i get message like this:

Server Error in '/infoDMS' Application.

Exception Details: Limilabs.Client.SMTP.SmtpResponseException: Authentication unsuccessful

Stack Trace:

[SmtpResponseException: Authentication unsuccessful]
Limilabs.Client.SMTP.Smtp.SendCommand(String command, Boolean throwException) +135
infoDMS.Poruke.PosaljiEmail(RadComboBox primatelji, String _subject, String _message) +1669
infoDMS.Poruke.SendMessageButtonClick(Object sender, EventArgs e) +1068
Telerik.Web.UI.RadButton.RaisePostBackEvent(String eventArgument) +307
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3804

Answer 1

Your SMTP server returns "Authentication unsuccessful" error, which means what it says - there was a problem with authentication.

Most SMTP servers require providing credentials before sending an email.

The StackTrace looks too short - it looks like if you were sending custom commands to the server, before authentication (before UseBestLogin method).

How does your code look like?