If you are consciously receiving the bounce back email like “The mail server detected your message as spam and has prevented delivery” after any panel updates you may please follow the below steps to prevent such bounce back emails. This can be done with Apache SpamAssassin™. Apache SpamAssassin is an email function that uses spam filtering and network tests to examine incoming email and test for spam characteristics. SpamAssassin checks the emails with an overall score to determine whether it should discard a message.

1) Login to WHM.

2) Navigate to Exim Configuration Manager.

3) Click on Filters tab in the Basic editor mode.

4) Now you can set Apache SpamAssassin™: bounce spam score threshold to 4. Then we get bounce back mail when the spam score is above this number. (positive or negative, single digit after a decimal point allowed). By default, the settings are set to No bouncing by spam score but we can change the settings to secure the server.

5) Click on save button to reflect the changes. Note: It is important to understand that making any of these changes will affect all email accounts on the entire server. You should, therefore, make sure all your clients are aware of the settings you are changing.

Now the error should be fixed. Now you can successfully send email to the server without getting any bounce back emails.