Enhanced status code

SMTP error X.1.4

Destination mailbox address ambiguous

Updated Jul 1, 2026

The short answer

Destination mailbox address ambiguous Common cause: Address maps to more than one recipient

Quick fix

Use the recipient's exact mailbox address

This code is written X.1.4 because the reason is the same whether the failure is temporary (a 4 first digit) or permanent (a 5). Read the first digit of your own bounce to know which applies.

How to fix it

Use the recipient's exact mailbox address

Related codes

X.1.0 Other address status X.1.1 Bad destination mailbox address X.1.2 Bad destination system address X.1.3 Bad destination mailbox address syntax X.1.5 Destination address valid X.1.6 Destination mailbox moved, no forwarding address
All SMTP error codes
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