Did you send an email and have it returned with a 550 error?
550 This message was classified as SPAM and may not be delivered
This means that something in the email contents or the way the email is being sent triggered our spam filter. When you send an email from your hosting account it must pass our outbound spam filters before it is delivered to your recipient. Our outbound spam filters have a very low false-positive rate which means that they rarely block legitimate emails. Here are a few common tips to help avoid this error:
Tip #1 Modify your subject and email content
Our outbound email servers use a spam evaluation process that is set moderately low. This means it is unlikely for your emails to be classified as spam and prevented from reaching your recipient unless they have multiple ‘spam’ characteristics. If you are still getting blocked by the spam filter, you will want to evaluate both the subject line and body content of your email.
- Avoid using a single word as the subject and if you do want to use a single word it should be a common dictionary word.
- Don’t use all caps in the subject line
- Avoid spelling mistakes
- Don’t use exclamation marks in the subject
- Common email spam words and phrases to avoid
Be amazed/your own boss
Double your income/cash
Get it now/started/paid
No credit check/experience
While supplies last
In addition to excluding these words from your email subject lines, there are a few other things you can avoid to limit the chance that your email will be picked up by spam filters.
- Don't add RE: to subject lines if it's not a reply
- Don't use all caps
- Don't make spelling mistakes
- Don't use one-word subject lines
- Don't use exclamation points in your subject line
- Don't embed forms in emails
Tip #2 Turn on SMTP Authentication if you use Outlook
Outlook tends to be causing email messages to score higher than normal, causing emails that otherwise would be allowed through to be classified as spam. This is commonly caused by not having SMTP Authentication enabled in Outlook. You need to make sure SMTP authentication is enabled in Outlook and the username is your full email address along with the password for your email account.
Tip #3 Contact us to check further
If you have worked with the other solutions above and are still having issues with your emails getting classified as spam, you will want to contact our Technical Support department. Simply forward the failed-email complete with the bounceback-headers to the Support-team and they will be able to test the email against the filter and find which rules were violated. You can also submit your returned email as a ticket via the customer portal.
Understanding outbound email filtering, What is it?
We have customizable spam filtering tools already in place for each account that evaluates incoming emails. Outbound SPAM filtering is a process where any outgoing emails will be checked as to the likelihood of the message being spam. This is not customizable on an account level and is handled by your hosting server. It checks for multiple characteristics and assigns points for any it finds. If the email reaches a certain level, it is classified as SPAM and not allowed to leave the server. If you are receiving a bounce-back with the error "550 This message was classified as SPAM and may not be delivered", then the email you sent has not passed the outbound filter.
Email to any recipient can always be determined to be spam based on content. The number of recipients for outbound emails are limited to 50, so it is not typically used as criteria in determining that an email is a spam. The recipient field is only used as criteria for allowing or disallowing emails when the recipient has been explicitly placed on a blacklist or whitelist. This can be done in Spam Assassin.
Why do you do Outbound email filtering?
Outbound screening helps to preserve the reputation of our server's IP addresses. If an email server's IP gets enough spam complaints against it, it will be reported and blacklisted by a blacklisting service. Any email server that subscribes to that service will then block any mails coming in from that IP address. It is also possible that any emails coming from any of our servers will eventually be automatically being delivered to spam folders, regardless of the IP address of the server. As most of our customers do legitimate business online, it would be unfair to allow our server IPs to be classified as spam because of a few abusers, hence the outbound spam evaluation.