Email Error 553

This article is for if you're receiving the following error when trying to send emails:

Server error: '553 sorry, that domain isn't allowed to be relayed thru this MTA (#5.7.1)'

553 email error is related to SMTP authentication not being used. Our mail server requires that you authenticate with a valid username and password before you're allowed to send an email out. 

You should receive a bounce-back message from the server with a variation of email error 553 in the subject, and the body should contain your original message that you attempted to deliver.


Please view the screenshot below, it is for Outlook's outgoing server settings but will apply to other email programs as well.



If you are using Outlook you can get to those settings by following these steps:


  • Click "File" then "Account Settings":



  •  Select your email address and click "Change":



  • Then click "More Settings":





  • Then click on the "Outgoing Server" tab and verify the settings are the same as shown here:


If you are still having issues, please submit a ticket via the Support Portal by CLICKING HERE.

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