Is a full mailbox a hard or soft bounce?

It is initially a soft bounce (4xx code). If the mailbox remains full for days and retries fail, your system will eventually record it as a hard bounce.

Should I remove full mailboxes from my list?

If an address consistently bounces due to being full over multiple campaigns, it's best to suppress it, as it indicates an abandoned account.

← Error library

452 4.2.2 Mailbox full (temporary)

temporary Mailbox

Meaning

The recipient's email inbox is full and cannot accept any new messages at this time.

Common causes

The recipient has exceeded their email storage quota.
The recipient has abandoned the account but it hasn't been deactivated yet.
The message being sent is large and pushes the mailbox over its limit.

How to fix

Your server will retry delivery. If the recipient clears space, it will be delivered.
If retries fail and it becomes a hard bounce, pause sending to this address.
Contact the recipient through another method to let them know their inbox is full.

Provider notes

Gmail. States 'The recipient's inbox is out of storage space. Please direct the recipient to Manage files in your Google Drive storage.'

Example bounce

452 4.2.2 The recipient's inbox is out of storage space.

FAQ

Is a full mailbox a hard or soft bounce?: It is initially a soft bounce (4xx code). If the mailbox remains full for days and retries fail, your system will eventually record it as a hard bounce.
Should I remove full mailboxes from my list?: If an address consistently bounces due to being full over multiple campaigns, it's best to suppress it, as it indicates an abandoned account.