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How to avoid having my messages being classified as spam?

Follow these general guidelines

  • Do not send mail from a non-existent e-mail address. This seems obvious, but many people still make mistakes against this rule. If it is a contact form or other (automatic) system that sends the mail, have the system send a test message to yourself and check the sender.
  • As a first step, you must create an SPF-record for your domain names. An SPF-record tells the mailboxes via which mail servers your e-mails are sent. It is a kind of tip to the spam filters to indicate which mails are legitimate and which are not.
    Read how to create an SPF record to stay out of the spam filters
  • Do you send a newsletter? Then there must be an option to unsubscribe – the header of the email should contain an item called list-unsubscribe. See http://www.listunsubscribe.com/ for more information on this topic.
  • Ensure a good balance between text and images. That is because spammers often use a technique to bypass spam filters that respond to words: they send one image, which contains all the text. So make sure you send more than one image and enough text – at least between 50 and 100 words.
  • Do not use too much white space. Use more condensed text when compiling your message.
  • Do not mark your mail as a High Priority.
  • Do not send mail from an e-mail address that is not yours. The SPF of the domain name will block you.
  • Never send bulk mailings via the shared mail server of the Combell hosting cluster. There are customized products for sending large quantities of mail, contact us for more information.
  • Send your emails using a mail server or tool such as Flexmail that support DMARC (or DKIM).

Take care and test your reputation

Take care of the reputation of your e-mail address. Check your reputation here

Use a free online mail test service to have your e-mail messages assessed.

This is an example:

  1. Go to the online page of the Mail tester
  2. Copy the e-mail address that you see on the homepage.
  3. Send an e-mail to the test e-mail address.
  4. You now get a score of how reliable your e-mail is.
  5. If you have problems, send our support team the link with the results for analysis.

Some remarks

There can be various reasons why people block your message.

Maybe it’s not you – but it’s them!
Remember that it is not only the sender who is responsible for ensuring that an e-mail gets past the spam filters. On the contrary, it is often the recipient who decides whether the message is spam or not.

Maybe you have a reputation!
Your message may be rejected due to the content (certain images, some keywords, certain code, or even capitalization).
If your message is in order, the spam filter of the recipient may be too strict.

However, if the message is immediately deleted upon receipt because the sender’s e-mail address is on a blacklist, it is up to the sender to correct this problem. In these cases, the sender is responsible for his reputation.

Updated on 7 March 2024

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