Error: 550 authentication

When sending mails, the mails bounce back with an error


Your message did not reach some or all of the intended recipients.

Subject: Dummy 3
Sent: 11/18/2014 3:21 PM

The following recipient(s) cannot be reached:

[email protected]' on 11/18/2014 3:21 PM
550 authentication.

'John Doe' on 11/18/2014 3:21 PM
550 authentication.



SMTP Authentication is not enabled i.e. the server is not able to verify your identity because the username and password have not been sent to it. 


Please ensure that SMTP authentication is enabled as per configuration. "My server requires authentication" should be selected.

In the Advanced Account Settings, you need to go to the Outgoing section and select the box which says "My Server Requires Authentication" or "EnableSMTP Authentication".

Also see:

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