// 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 Microsoft 365
| Problem | In short | Tags | |
|---|---|---|---|
| Your emails land in Outlook or Hotmail junk | Outlook.com, Hotmail and Live send many new senders to Junk. Check your setup, then use Microsoft's free sender tools: SNDS, JMRP and the delist portal. | Fix it | |
| Set up SPF, DKIM and DMARC for Microsoft 365 | A complete checklist to authenticate a domain that sends with Outlook in Microsoft 365: the SPF include, the two DKIM CNAME records, and a first DMARC record. | Fix it | |
| Microsoft 365 "550 5.1.8 Access denied, bad outbound sender" | Microsoft 365 has blocked a user from sending because the account sent spam, usually after being hacked. Secure the account, then unblock it. | Fix it | |
| DKIM with CNAME records: delegated selectors (Microsoft 365, SendGrid…) | Many providers ask for DKIM as CNAME records instead of a TXT key. Here is how they work and the mistakes that break them. | Fix it |
Not sure what is wrong?
Send a test email or scan your domain: the report tells you which problem you have.