Why your emails land in spam, in plain words
You send a quote, the customer never replies, and two weeks later they find it in their spam folder. Often the reason is three small settings on your domain that nobody set up.
This week I checked the email setup of a business I build websites for. It had no SPF record, no DMARC record and no DKIM signature I could find.
The three settings, in plain words
SPF is a public list of the servers allowed to send email for your domain. Without it, any server can claim to be you.
DKIM is a signature on every email you send, so the receiving server can tell it really came from your domain and was not changed on the way.
DMARC is your instruction for what to do with email that fails those checks, plus reports of who is sending email as you.
Since 2024 Gmail has required every sender to have at least SPF or DKIM set up. Mail without them is far more likely to be filtered.
The setting that looks done and does nothing
An SPF record ends in a short instruction. ~all asks the receiving server to treat mail from anywhere else as suspicious. ?all tells it to take no view at all, so the record is published and does nothing. It is a common default, which is why it is worth checking even if someone told you SPF is set up.
How to check yours in two minutes
Send an email from your business address to a Gmail address. Open it in Gmail on a computer, click the three dots next to Reply and choose Show original. Near the top you will see SPF, DKIM and DMARC. If any of them is missing or says FAIL, that is your answer.
The free website test checks these records too, in its “Email that arrives” section.