Outgoing Email Labeled as Spam when using a 3rd Party Email Client

Emails sent from the cPanel VPS or Dedicated server are being bounced back with 550 errors by the outgoing SpamAssassin spam filter when using email clients such as Outlook, Thunderbird, Mac Mail, etc. This guide covers the steps to adjust the outgoing filter.  The error message may appear as

550 This message was classified as SPAM and may not be delivered. 

SpamAssassin as cpaneleximscanner detected OUTGOING smtp message as spam

Adjust Outgoing SpamAssassin Filter

CAUTION: Disabling the outgoing spam filter is not recommended, as it would allow actual spam emails out.

NOTE: Unmonitored email or a high outgoing spam score can harm your mail reputation and increase the risk of hackers sending spam, causing damage.

IMPORTANT: This solution will require root access. If this needs to be obtained, follow the guide on requesting root access.

1. Log into Root WHM
2. Click Exim Configuration Manager
   
3. Navigate to the Basic Editor tab and select the Apache SpamAssassin™ Options tab
4. To disable the filter, set "Scan outgoing messages for spam and reject based on the Apache SpamAssassin™ internal spam_score setting" to Off
   
5. Enable "Scan outgoing messages for spam and reject based on defined Apache SpamAssassin™ score"
6. Set the score to desired spam score
   NOTE: The recommended value is 15, but it can depend on your server. The lower the score, the more strict the spam filter is.
7. Once the change is made click Save