To combat spam emails, all outbound email is currently being scanned to identify spam messages. The main reason for the scan is because of thousands of spam emails that are regularly being auto-generated through malware scripts. Email that is being identified as spam will generate the following in a bounce-back email:
550 This message was classified as SPAM and may not be delivered
An increase in outbound spam email is not unusual at this time of the year. Spam messages can cause a server to be blacklisted, and cause unnecessary use of server resources that may lead to slow load times of the websites hosted on that server. The scan and other security measures have been put in place to help stop this from happening.
My outbound email is being flagged as spam, what do I do?
If you find that you have many bounce-back messages identifying your outbound email as spam, then please submit a verified email ticket to our live technical support team. Attach a copy of one of the bounce-back messages to that email. The technical support team can scan your account and identify any possible malware generating messages from your hosting account. You should also submit a ticket (with the bounce-back message) if you believe that your emails are being falsely identified as spam. The support team will be able to tell if a false positive is being generated for your account.
You should also take the time to read Why does SpamAssassin label my email as spam? This tutorial includes the list of common items that may cause your messages to be flagged as spam.