Why do my emails land in spam? The most common causes and the two-minute check
Your emails end up in the recipients' spam folder? Usually the domain lacks technical authentication (SPF, DKIM, DMARC). The causes in order of frequency — and how to check in two minutes which one applies to you.
The short answer: in most cases emails land in spam because the sending domain cannot prove to the recipient that the message really comes from it. Three DNS records exist for exactly that — SPF, DKIM and DMARC — and at most businesses at least one of them is missing or broken. Whether that is true for you takes two minutes to find out: enter the domain into the check, and the traffic light shows what is missing and how to repair it.
Only after that do reputation and content come into play. Google, Microsoft and Yahoo decide in this order: Is the sender technically authenticated? Do the domain and the sending address have a good reputation? Only then does the content matter. Here are the causes, sorted by how often they occur in practice.
Cause 1: SPF, DKIM or DMARC are missing or broken
By far the most common cause. Since Google and Yahoo began enforcing their sender requirements in 2024, unauthenticated mail has been treated systematically worse — and for bulk senders it is simply rejected. Typical cases: no SPF record at all, two SPF records (which makes the check invalid), DKIM never activated in the mail provider's portal, DMARC record missing entirely. The good news: this exact layer can be fully repaired with a handful of DNS records — at any hoster, whether Strato, World4You or Cloudflare.
Cause 2: Your sending service sends without your domain
Newsletter tools, shops or invoicing software send with your sender address, but they are neither listed in your SPF nor signing with your DKIM. To the recipient this looks like a forgery — and from DMARC quarantine/reject onwards it is treated as one. Solution: verify your own domain with the respective service (this generates its DKIM records) and add the service to your SPF.
Cause 3: A new domain or a sudden spike in volume
Reputation is built over weeks. A freshly registered domain that sends hundreds of emails on day one looks like a spam campaign to every filter. What helps: start small and increase volume over two to four weeks ("warm-up"), encourage replies and address-book entries from recipients — and have the technical setup from cause 1 in place BEFORE the first send.
Cause 4: Purchased or outdated address lists
High bounce rates and recipients marking you as spam ruin reputation faster than any technical setup can rescue it. Google draws the line at a spam complaint rate of 0.3% — above that, delivery is throttled. Only send to recipients who have consented; remove undeliverable addresses from the list immediately. In Austria this is required anyway: advertising emails need prior consent (§ 174 TKG, the Austrian Telecommunications Act), even when sent to businesses.
Cause 5: Content, links and attachments
Only in fifth place — and far less often than most people assume: links to domains with a bad reputation, link shorteners, huge images without text, executable attachments, an email that consists of nothing but one image. Individual "spam words" in the subject line, on the other hand, are overrated: modern filters weigh authentication, reputation and recipient behaviour. No reputable newsletter fails because of a word like "free", but it certainly does because of missing DKIM.
How to make sure your emails do not land in spam
- Check the domain: verify SPF, DKIM and DMARC in two minutes — the report lists the missing records ready to copy.
- Set SPF: exactly ONE TXT record that names all your sending services (guide).
- Activate DKIM: at every service that sends in your name — mail provider, newsletter tool, shop (guide).
- Roll out DMARC: start with p=none and a reporting address, tighten after a few weeks (step-by-step plan).
- Send a test email to a Gmail mailbox and open "Show original" there: spf=pass, dkim=pass, dmarc=pass is the state you want to see.
- Only send to recipients who have consented; remove bounces immediately; ramp up new domains slowly.
Frequently asked questions
What can I do so that my emails do not land in spam?
Set or repair the three DNS records SPF, DKIM and DMARC for your domain, include every sending service in them, only send to recipients who have consented, and ramp up new domains slowly. The mailampel check shows in two minutes which of these points is open for your domain.
How do I find out whether my domain is the problem?
Enter the domain into the free check: the traffic light rates SPF, DKIM, DMARC and the other records and lists the missing values ready to copy. In addition, send a test email to a Gmail mailbox and open "Show original" there — spf=pass, dkim=pass and dmarc=pass are the goal.
Why do my emails not arrive at Gmail, but do at other providers?
Google enforces the sender requirements most strictly: without SPF and DKIM (and, for bulk senders, additionally DMARC and one-click unsubscribe), mail is filtered out there first. That makes Gmail the best early-warning system — what arrives there arrives almost everywhere.
Does it help to ask recipients to save me as a contact?
As a supplement, yes — address-book entries and replies improve personal delivery. But it does not replace technical authentication of the domain: that works with all recipients, including those who do not know you.
How long until repairs take effect?
DNS changes take effect within minutes to hours, depending on the TTL. Reputation follows more slowly — after a broken setup it typically takes a few days to a few weeks for delivery to return to normal.