550 5.1.4 Destination mailbox address ambiguous

Meaning

The mailbox address matches multiple recipients.

Common causes

• Ambiguous alias.
• Directory misconfiguration.

How to fix

1. Use a specific address.
2. Contact recipient admin.

Example bounce

550 5.1.4 Destination mailbox address ambiguous

Related codes

• 550 5.2.4 Mailing list expansion problem
• 452 4.2.2 Mailbox full (temporary)
• 501 5.1.3 Bad destination address syntax