Key points at a glance
- Usually a technical problem is to blame, not the content of your emails.
- Missing or faulty SPF, DKIM and DMARC records are among the most common causes.
- Newsletter tools, webshops and accounting software also need to be set up for your domain.
Cause 1: SPF, DKIM or DMARC missing or wrong
Large mailbox providers such as Google, Yahoo and Microsoft now require senders to identify themselves. If DMARC is missing, SPF is invalid, or a service sends without DKIM, trust in your emails drops significantly.
- Sender identified?SPF, DKIM and DMARC are set up and pass.
- Server clean?Your mail server’s address is on no blacklist.
- Behaviour unremarkable?Steady volumes, few spam reports and bounces.
- InboxThen your email has a good chance of reaching the inbox.
Mandatory for bulk senders since 2024
Anyone sending more than 5,000 emails a day to Gmail or Yahoo addresses has needed SPF, DKIM and DMARC since 2024. Microsoft has required the same since 2025 for private Outlook and Hotmail addresses.
Cause 2: your mail server is on a blacklist
Blacklists collect IP addresses that spam has come from. If an account of yours was misused, or you share an address with others, your server can end up on one. Many recipients reject emails from listed addresses.
Cause 3: services send in your name
A newsletter tool, webshop or accounting software sends with your sender address but is not listed in SPF and doesn’t sign with DKIM for your domain. To recipients, these emails look like forgeries.
Cause 4: behaviour and content
- Suddenly far more emails than usual, for example with a first newsletter.
- Many recipients mark your emails as spam; newsletters are missing a simple unsubscribe link.
- Address lists with outdated addresses that cause too many bounces.
Tip for your first newsletter
Send newsletters through a dedicated service and set up SPF and DKIM for it with your domain before the first mailing goes out.
What to do
- Check and fix SPF, DKIM and DMARC for every sending domain.
- List all services that send in your name and set up SPF and DKIM for each.
- Check blacklists and request delisting once the cause has been fixed.
- Handle bulk mailings through a dedicated service with a clean unsubscribe process.
How DomainRadar helps
DomainRadar continuously checks SPF, DKIM and DMARC, monitors the IP addresses of your mail servers against blacklists and shows in the DMARC reports which services send in your name and whether they are set up correctly.
The domain check stays free. Afterwards you test Business for 14 days – no credit card, the trial ends on its own.