550 5.7.515: Authentication level not met (Outlook.com)
Outlook.com rejected your mail because your domain fails the SPF, DKIM and DMARC checks Microsoft requires from high-volume senders. This applies to Hotmail and Live addresses too.
Blocked The address is probably fine. The problem is how the mail was sent.
What the bounce message looks like
The wording changes from one provider to another. These are typical examples:
550 5.7.515 Access denied, sending domain [example.com] doesn't meet the required authentication level.Common causes
- Sending 5,000 or more messages a day to Microsoft consumer addresses without SPF, DKIM and DMARC all passing
- A missing DMARC record, or SPF or DKIM that doesn't match your From domain
How to fix it if you sent the email
- Set up SPF, DKIM and DMARC (at least p=none) so that they pass for your From domain.
- Check with the DMARC checker, then send again.
If you manage the receiving or sending mail system
- Microsoft started enforcing these requirements for high-volume senders to its consumer addresses in May 2025.
Free tool: paste the full bounce into the bounce message decoder to get a plain-English reading of every code in it.
Questions people ask
- What does 550 5.7.515 mean?
- Outlook.com rejected your mail because your domain fails the SPF, DKIM and DMARC checks Microsoft requires from high-volume senders. This applies to Hotmail and Live addresses too.
- Is 550 5.7.515 a hard or soft bounce?
- Blocked. The address is probably fine. The problem is how the mail was sent.
- Should I remove the address after a 5.7.515 bounce?
- No. Fix how the mail is sent; the address itself is probably fine.