How to Fix 550 Email Rejection Errors

A 550 error is one of the most common email bounce codes. It means the receiving server permanently rejected your message. Here's what causes it and how to fix it.

Common Causes of 550 Errors

• SPF failure - your sending server isn't listed in your domain's SPF record
• DKIM failure - no valid DKIM signature on the outgoing message
• Domain or IP blacklisted - the receiving server has blocked your domain or mail server
• Recipient address doesn't exist - the address you're sending to is invalid
• Recipient server policy rejection - their server has strict filtering rules blocking your messages

How to Fix a 550 Error

1. Check your SPF record - log in to cPanel, go to Email > Email Deliverability, and verify SPF is correctly set up for your domain.
2. Enable DKIM - on the same Email Deliverability page, ensure DKIM is installed and active.
3. Check blacklists - visit mxtoolbox.com/blacklists and run a check on your domain and server IP.
4. Verify the recipient address - double-check for typos.
5. Contact the recipient's IT team - if their server is blocking you specifically, they may need to whitelist your domain.

Reading the Full Error

550 errors usually include a description after the code - for example, 550 5.7.1 Message rejected due to SPF policy. Read the full message for clues. Need help deciphering an error? Contact our support team.