Symptoms

The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.1 Client was not authenticated
 

Diagnoses

During our webEx meeting with the customer we tried the following and none seem to resolve the error:

- Changed Authentication to "Plain" with and without the username and password.
- Changed Authentication to "Windows" with and without the username and password.
- Changed Authentication to "Anonymous" with and without the username and password.
- Re-ran K2 configuration wizard with the option "Reconfigure"

Please note that after each and every change done we ensured that K2 Hostserver service is restarted.

We double checked that Anonymous users are allowed to send mail on the relevant connector on the exchange server.
 

Resolution

It was later found that the parameter for "Mail Server" in the String Table on workspace was not up to date. After this was corrected all processes in error state were retried and email event started working. This was due to new version of the processes deployment the previous day.