Fix "550 5.7.1 not permitted": Sending to this recipient is not permitted from your IP

Getting 550 5.7.1 not permitted? It means sending to this recipient is not permitted from your IP.

How to fix it

Fix authentication and reputation, or move to a trusted dedicated IP.

Prevent it

• Authenticate with SPF, DKIM and DMARC.
• Use a dedicated IP.
• Keep bounce and complaint rates low.

How Rainmail helps

Rainmail sends from your own domain on a dedicated, isolated IP with SPF, DKIM, DMARC, reverse-DNS and managed warm-up handled for you, a REST API, and an AI watching deliverability — and it welcomes senders SES, SendGrid and Mailchimp reject, from $8. Run the free checker or see plans.