SPAM: Why was my email blocked?

All mail sent from the shared hosting services is sent via a spam-filtering outbound mail gateway. 
This is to protect the IP reputation of our servers. Therefore, the deliverability of all emails sent from our cPanel and Plesk shared web hosting servers.

This mail gateway examines every email sent from the shared server, considers its contents, and applies a numeric ‘spam score’.  When a mail’s ‘spam score’ exceeds a certain threshold, it is considered to be spam and blocked.

When mail you send is blocked by our mail gateway. This is because it has been recognised as SPAM. If a block has happened, you will receive a ‘bounce’ message, which may have a subject similar to:

Mail delivery failed: returning message to the sender

It can be hard to make sense of the email headers included in these emails.
Essentially, some characteristics of the email caused our mail gateway to suspect that it was spam.

Throughout this article we detail some common block reasons and potential fixes:

Links which look like phishing links

A common tactic of spammers is to send email phishing links.
These links imitate real sites, leading to fake sites and sometimes high-quality copies.

Their purpose is to trick the person who clicks a link into believing they are on the authentic site. Potentially entering personal details.

If you have a similar type of hyperlink in your email. Then the mail filter is likely to suspect foul play.
This is quite easy for our support team to diagnose and the solution is easy. Fix or remove the link.

Invalid or missing SPF records

SPF records are a special type of DNS record that identify the mail servers which are authorised to send mail on behalf of a domain. 

Large mail service providers such as Gmail and Hotmail increasingly take note of these and, when a message is received, check to make sure that the mail was sent from a server that is authorized to send emails on behalf of the domain.

If you are using a domain that is resolving from the DNS configured in your cPanel or Plesk account, your domain should already have a valid SPF record, but if you are using an external DNS provider you should contact our support team to check that your SPF record is set up correctly.

Spam trigger words or phrases

It could be that the content of your message, or the subject, happens to be using keywords that are commonly seen in spam emails.  Some examples of these are:

  • Free Offer
  • WORDS OR PHRASES ALL IN CAPITALS (particularly in the subject)
  • Lots of exclamation marks!!!
  • Sale
  • Generic salutations, such as ‘Dear Customer’
  • Banking terms such as Statement, Invoice
  • Phrases encouraging users to sign in, for example ‘Sign in’, ‘Log in’, ‘authenticate’

Obviously some of the above are perfectly legitimate, but together they may contribute to the ‘SPAM score’ of an email which increases the chances of your mail being misidentified.

Attachments and images

Some spammers attempt to hide contents from spam filters by using images instead of text, and some phishing emails include attachments which they are aiming to trick recipients into the opening. 

As such, emails with low ‘text to image ratios’, i.e. just a small amount of text alongside one or more images or attachments, can sometimes attract a ‘spam score’.

No Subject / special characters / strange spacing

Emails without a subject at all are unusual, and as such likely to be viewed with suspicion.  Similarly, another trick used by spammers is to try to hide the content of messages by using unusual character sets or S P A C I N G in text, to try to hide the content of the message from spam filters.  As such try to stick to standard characters and formatting where possible.  

None of the above applies to my mail!

These are just a small sample of some of the more common reasons why mail has been identified as spam and blocked. 

If you would like some further insight on why a particular email was blocked, please contact our support team by raising a ticket through your client area of the website, and providing the from address, to address, and rough time at which the email was sent (note the logs of the mail filter are only retained for a couple of days, so it will need to be ‘recent’) and we will investigate for you.