550 5.1.1
550 5.1.1 User Does Not Exist
The iCloud mailbox never existed or has been permanently deleted.
Treat 5.1.1 as a hard bounce. Continuing to retry can damage IP and domain reputation with Apple.
Severity
ERROR
Provider
Apple Mail (iCloud)
Last Reviewed
2025-06-01
How to Fix 550 5.1.1
Follow these steps to resolve this Apple Mail (iCloud) SMTP error and restore normal delivery.
- ✓Remove the address from your list immediately and do not retry.
- ✓Offer double opt-in or confirmed opt-in for Apple subscribers.
- ✓Validate customer data during checkout or form submission.
- ✓Alert customer success teams when key contacts disappear so they can confirm replacements.
Helpful Resources
More Apple Mail (iCloud) SMTP Codes
Keep these related troubleshooting guides handy while addressing 550 5.1.1.
Still experiencing Apple Mail (iCloud) delivery issues?
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