Chapter 9 · 9.4
My mail ends up in the recipient's spam folder
Does your mail end up in customers' spam folders, or do you get mail back from Gmail or Outlook.com referring to SPF, DKIM or DMARC? Then the receiving mail server doesn't trust that the mail really comes from you. This is usually down to a few settings in your DNS, and you can fix them in a few minutes.
The three authenticity features: SPF, DKIM and DMARC
| Feature | What does it do? | Setting it up |
|---|---|---|
| SPF | States which servers are allowed to send mail on behalf of your domain. If you also send mail through a newsletter service or accounting package, that needs to be included too. | Setting up and adding to SPF |
| DKIM | Adds a digital signature to each message, so the recipient can see it hasn't been changed in transit. | Turning on and checking DKIM |
| DMARC | Tells the recipient what to do with mail that doesn't pass SPF or DKIM. | Setting up DMARC |
Large mail services such as Gmail, Outlook.com and Yahoo are increasingly strict about these features. If one is missing, your mail is more likely to end up in spam or be rejected.
Step 1: check your domain
Our website has the free Email Health Check: www.weboke.nl/en/emailcheck. Enter your domain name and within seconds you'll see whether your MX records, SPF and DMARC are set up correctly, and whether the mail server is on a blacklist. You'll get a score and practical advice.
A second check is Domain health: www.weboke.nl/en/domein-gezondheid. This looks at the basics of your domain, such as nameservers, SSL, DNSSEC and DMARC. If you're logged in and it's your domain, you can have some issues fixed straight away there.
Step 2: send a test mail
Want to know how a real mail from you is assessed? Use a testing service such as mail-tester.com. You send a mail to the address the site gives you and receive a report with a score and suggestions for improvement, including the results for SPF, DKIM and DMARC.
Other causes
- You send mail through another service. Does your newsletter go out through Mailchimp, MailerLite or Laposta, or does your accounting package send invoices on behalf of your address? Then you also need to have your domain verified with that service. The service will give you the records to add to your DNS (usually a TXT or CNAME record, see TXT records for verification (Google, Microsoft and others) and Setting up and adding to SPF).
- The content looks like spam. A mail containing only a large image, lots of links, shortened links, words like FREE in capitals, or an attachment with macros scores poorly. Write plain text with a clear sender and subject.
- You send a lot of mail at once from your mailbox. A regular mailbox isn't meant for newsletters to hundreds of addresses. Use a newsletter service for that. There's also a sending limit of 300 mails per day per package (see Send limits and the 'message limit reached' message).
- Forwarding to Gmail or Outlook.com. If you forward mail from your own address to a free mail service, that service may see the forwarded mail as spam, because the original sender doesn't match the server delivering it. It's better to retrieve your mail using IMAP instead of forwarding it (see Forwarders: forwarding mail to another address).
- Microsoft is extra strict. Outlook.com, Hotmail and Microsoft 365 move mail from unknown senders to the Junk Email folder more quickly. Ask your regular contacts to add your address to their contacts or safe senders.
- A blacklist. If the server you send mail with is on a blacklist, your mail is often rejected entirely. See Verzenden geweigerd: blacklists en limieten for more on this.
Tip: Have you just changed SPF, DKIM or DMARC? A change to your DNS isn't always visible everywhere straight away (see When does a change take effect? Waiting time and TTL). Test again after an hour.