550 5.2.4 Mailing list expansion problem

Meaning

The mailbox is a mailing list address and could not be expanded.

Common causes

• List is broken.
• Configuration error.

How to fix

1. Contact list admin.

Example bounce

550 5.2.4 Mailing list expansion problem

Related codes

• 550 5.1.4 Destination mailbox address ambiguous
• 452 4.2.2 Mailbox full (temporary)
• 501 5.1.3 Bad destination address syntax