Sender or policy problem
Email error 550 5.7.1: Message rejected by policy (blocked)
The receiving server refused the message because of a policy decision, not because the mailbox is missing. The sender, the sending IP or the content was judged unwanted.
Common causes
- The sending IP or domain is on a blocklist.
- SPF, DKIM or DMARC is missing or failing.
- The message looks like spam to the filter.
- The recipient network only accepts mail from approved senders.
How to fix it
- Read the text after the code: many providers name the reason or a help link.
- Check SPF, DKIM and DMARC for your sending domain.
- Check your sending IP and domain against public blocklists and request removal if listed.
- Reduce volume, clean the list and send only wanted content, then try again later.
Clean a whole list · MX lookup · SPF, DKIM and DMARC checker
Frequently asked questions
Does 5.7.1 mean the address is invalid?
No. The mailbox may be fine. The rejection is about the sender or the message.
Should I remove the address?
Not automatically. Fix the sending problem first and test with a small batch.
Other error codes
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