554 5.7.1 is a permanent SMTP reply meaning message refused / blocked by policy. The server connected and then refused delivery. 5.7.1 is the "delivery not authorized / message refused" enhanced status — the receiver decided not to accept this mail from you.
What 554 5.7.1 means
The server connected and then refused delivery. 5.7.1 is the "delivery not authorized / message refused" enhanced status — the receiver decided not to accept this mail from you.
Common causes
Your sending IP or domain is on a blacklist
Most commonA poor IP/domain reputation is the leading cause of a flat 554 5.7.1 refusal at Gmail, Outlook, and corporate filters.
SPF, DKIM, or DMARC is failing
CommonAuthentication failures cause many receivers to refuse mail outright, especially after the 2024 bulk-sender rules.
Content tripped a spam or security filter
Less commonRisky links, spoofed-looking headers, or malware signatures can produce a policy refusal.
How to fix 554 5.7.1
- 1
Check your blacklist status
Run a free EmailHealth check to see whether your domain or sending IPs are on SpamCop, Barracuda or other blocklists — then follow the relevant delisting guide.
- 2
Confirm SPF, DKIM, and DMARC all pass
Authentication failures are an easy and common cause. Verify all three are aligned for your sending domain.
- 3
Read the full bounce text
Receivers often append a URL or reason after 554 5.7.1. Follow it — it frequently names the exact block (e.g. a specific blacklist or a postmaster page).
Confirm your domain is set up correctly
Most delivery failures — permanent or temporary — trace back to authentication or reputation. Run a free EmailHealth check to confirm SPF, DKIM, DMARC, blacklist status, and TLS are all healthy for your sending domain. If you send in volume, free daily monitoring will alert you before a small issue becomes a flood of bounces.