You send an important email — a quote, an invoice, a reply to a new enquiry — and it never gets read. Days later you hear the dreaded line: “Oh, it went to my junk folder.” If that’s happening to you, the good news is it’s rarely random, and it’s almost always fixable. Here’s what’s really going on, in plain English.
It’s usually about trust, not content
Most people assume junk filtering is about what you wrote — a spammy word here, too many links there. That plays a small part, but the much bigger factor is whether the receiving mail server can prove the email genuinely came from you.
Email was invented without any built-in way to check the sender’s identity, which is exactly why spammers and scammers can pretend to be anyone. To fight back, providers like Microsoft and Google now check every incoming message against three behind-the-scenes records on your domain. If those records are missing or set up wrong, your perfectly legitimate email looks suspicious — and gets quietly filed under junk.
The three records that decide your fate
These have unfriendly names, but the idea behind each is simple:
- SPF — a list of who’s allowed to send email for your domain. Think of it as a guest list on the door. If your email comes from a server that isn’t on the list, it looks like an impostor.
- DKIM — a tamper-proof seal on each message. It lets the receiver confirm the email really came from your domain and wasn’t altered on the way.
- DMARC — the policy that ties the other two together and tells receivers what to do if a message fails the checks (and quietly reports who’s sending in your name). Without it, mailbox providers are increasingly likely to distrust you by default.
When all three are in place and correct, your email arrives looking trustworthy. When they’re missing, mismatched, or half-finished — which is incredibly common — your messages get penalised through no fault of your own.
Since 2024, Microsoft, Google and Yahoo have actively required proper authentication for anyone sending business email — so getting this wrong now costs you far more than it used to.
The other usual suspects
Authentication is the big one, but a few other things can tip you into the junk folder:
- A poor sender reputation. If your domain (or the server you send from) has a history of bouncing, spam complaints, or sat on a shared IP with bad neighbours, providers trust it less.
- A brand-new or rarely-used domain. Sending a sudden burst from a domain with no track record looks exactly like what a spammer does.
- Being on a blocklist. Sometimes a past compromise or a misconfigured server lands your domain on a public blacklist without you knowing.
- Spam-trigger content. ALL CAPS subject lines, “FREE!!!”, lots of links or big images with little text, and broken unsubscribe links all nudge the filters.
- No recipient relationship yet. A first-time cold email to someone who’s never mailed you back starts with less goodwill than a long-running conversation.
How to find out what’s wrong
You don’t need to guess. Most deliverability problems show up the moment you look at your domain’s SPF, DKIM and DMARC records — and you can check all three in seconds.
We built a free email security checker that does exactly this: pop in your domain and it reads your records, tells you in plain English what’s set up properly and what isn’t, and flags the gaps that are most likely sending you to junk (and leaving you open to spoofing). No jargon, no sign-up.
How to put it right
Once you know where the gaps are, fixing deliverability usually comes down to a handful of steps:
- Get SPF, DKIM and DMARC set up correctly. This is the single biggest lever — and the one most businesses haven’t fully pulled. Done properly, it’s a one-off job with a lasting payoff.
- Make sure every sending service is authorised. Your accounting software, CRM, marketing platform and booking system all send “as you” — each one needs to be on the guest list, or its mail gets flagged.
- Check you’re not on a blocklist, and if you are, deal with the cause and request removal.
- Tidy up your content and lists. Clear sender name, a real reply-to address, a working unsubscribe link, and no buying dodgy contact lists.
- Keep your domain healthy. Send consistently rather than in sudden floods, and keep an eye on the DMARC reports so problems surface early.
The bottom line
Emails landing in junk almost always trace back to a small set of fixable settings — and authentication is nearly always at the heart of it. It’s worth sorting properly, because the same records that keep you out of the junk folder are what stop criminals spoofing your domain to scam your customers and suppliers. One fix, two big wins.
Not sure where your domain stands? It takes about ten seconds to find out — and if anything needs fixing, we’re happy to help you get it sorted properly.