Why emails land in spam (and how to fix it)

If you are wondering why your email lands in spam, here is the good news: in the vast majority of cases the cause is technical and can be fixed in a single evening. The recipient server (Gmail, Outlook, a corporate Exchange) works like a doorman at the gate - before letting a message into the inbox, it checks whether the sender is trustworthy. If you cannot prove who you are, you end up in spam or the message never arrives at all.

The most common cause is missing email authentication - no SPF, DKIM and DMARC records in the domain DNS. Since 2024 Gmail and Yahoo require them explicitly - without them even an honest email looks like a spoofing attempt. The second group of causes is reputation: the server IP or your domain appears on a blacklist (such as Spamhaus) because someone on the same shared server was spamming, or the server has no valid reverse DNS (rDNS) - meaning the IP address does not "introduce itself" with any name. The third group is the content itself: subject lines in ALL CAPS, dozens of links, trigger words like "free" or "promotion", or a message that is one big image.

How do you check whether your email lands in spam? Start with a diagnosis, not with guessing. The free test at /test-poczty checks in seconds whether your domain has valid SPF, DKIM, DMARC and MX records and gives it an A-F grade with a list of specific gaps. You can also send an email to your own Gmail account and choose "Show original" - you will see the SPF/DKIM/DMARC results (pass or fail) in black and white.

How do you fix it? Step by step: generate an SPF record in a minute at /spf-generator, DMARC at /dmarc-generator, and enable DKIM in your email provider panel. On top of that, check the blacklists (mxtoolbox), ask your host for a correct rDNS entry and clean dead addresses off your mailing list - a high bounce rate also ruins your reputation. You will usually see results within a few days.