// how to fix
How to fix email problems
Your test or scan found a problem? Find the matching guide below: what it means, why it matters, and how to fix it step by step.
DNS 33
DMARC 28
SPF 28
DKIM 26
Reputation 24
Bounce 16
Security 16
Blacklist 13
Gmail 13
Content 12
Mailing list 11
Spam score 10
Headers 9
Reverse DNS 7
Mail server 4
Microsoft 365 4
MX 4
Outlook 4
TLS 2
Apple 1
BIMI 1
E-commerce 1
Google Workspace 1
WordPress 1
Yahoo 1
Zoho 1
4 guides · tag Mail server
| Problem | In short | Tags | |
|---|---|---|---|
| Running your own mail server: the deliverability checklist | A self-hosted Postfix server can deliver well, but only if every basic is right: reverse DNS, SPF, DKIM, DMARC, TLS and no open relay. | Fix it | |
| How to set reverse DNS (PTR) at your hosting company | The PTR record of your server IP is set by your hosting company, not in your domain DNS. Here are the general steps at OVH, Hetzner, Scaleway, AWS and DigitalOcean. | Fix it | |
| Your mail server is an open relay | An open relay lets anyone on the internet send email through your server. Spammers find it within hours and your IP ends up blacklisted. | Fix it | |
| "554 5.7.1 Relay access denied" when sending | Your mail server refuses to pass your email on because you are not logged in. Usually a missing SMTP login or the wrong port in your app or printer. | Fix it |
Not sure what is wrong?
Send a test email or scan your domain: the report tells you which problem you have.