Support article
550 permanent failure for one or more recipients blocked: how to fix it
Learn why the 550 permanent failure blocked error appears and what to review so your emails can be delivered correctly.
Introduction
The 550 permanent failure for one or more recipients (... blocked) error appears when a remote server permanently rejects your email.
In other words, the message left your account, but the recipient provider decided not to accept it. This can happen because of an incorrect address, a recipient antispam policy, poor IP reputation, domain authentication problems or suspicious content in the message.
Steps to fix the error
1. Read the full bounce message
The returned message usually includes important clues: rejected address, remote server, blocking reason and exact code.
2. Check the recipient address
Make sure the email address is correct. If the address does not exist or was disabled, delivery will keep failing.
3. Try sending to another recipient
Send a message to another account, ideally from a different provider. If it fails only with one address, the block may be on the recipient side.
4. Review the message content
Avoid aggressive subject lines, shortened links, suspicious attachments, excessive uppercase text or typical spam wording.
5. Check whether your IP or domain is blacklisted
You can use reputation tools to verify whether the mail server or domain appears on antispam blocklists. If you find a listing, report it to support.
6. Verify the mail DNS records
Make sure your domain has SPF, DKIM and, when appropriate, DMARC configured correctly. These records help prove that your messages are legitimate.
7. Avoid unauthorized bulk sending
If you send to old, purchased or unverified lists, bounce rates and complaints will rise and may trigger blocks.
8. Contact miHosting support
If your domain is hosted with miHosting and you suspect a reputation problem, open a support ticket and include the full bounce message so the technical team can review it.
Useful tips
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Do not delete the bounce message
The complete error text is key for diagnosis.
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Keep your recipient lists clean
Remove invalid addresses or contacts that bounce repeatedly.
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Configure SPF, DKIM and DMARC
These records do not guarantee delivery, but they improve trust with receiving servers.
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Protect your domain reputation
Reputation is built through legitimate sending, low complaint rates and good authentication practices.
FAQ
Does 550 blocked always mean my IP is blacklisted
No. It can be a blacklist, but it can also be a recipient policy, suspicious content or a nonexistent address.
Can I ask the recipient to unblock me
Yes. If it fails only with one specific recipient, that person or their mail administrator can review filters, blocked lists or quarantine.
Do SPF, DKIM and DMARC solve every block
Not every one, but they help a lot when other servers evaluate whether to trust messages sent from your domain.
Conclusion
The 550 permanent failure blocked error means the recipient server rejected the message.
Review the bounce, confirm the address, verify your reputation and make sure the domain authentication records are configured correctly. If you need help, send the full bounce message to miHosting support.