Skip to content
Webmaster Tools
EmailEmail Deliverability552 5.2.2

552 5.2.2 mailbox full

What the 552 5.2.2 bounce means, why mail to a full mailbox is rejected or deferred, how it differs from 452 4.2.2 and 552 5.3.4, and what senders and owners can do.

What 552 5.2.2 means

A 552 5.2.2 bounce means the recipient's mailbox is full, so the server cannot store your message. The basic code 552 is "requested mail action aborted: exceeded storage allocation" (RFC 5321), a permanent failure. In the enhanced status code (RFC 3463), subject 2 is about the mailbox and 5.2.2 is "mailbox full".

Gmail's wording is along these lines:

552-5.2.2 The email account that you tried to reach is over quota.

Other servers say "Mailbox full", "Quota exceeded" or "user is over quota". Wording differs between providers and versions.

552 vs 452

RFC 3463 notes that "mailbox full" is usually a temporary condition: the owner can delete mail. Many servers therefore reply 452 4.2.2 instead, which tells your server to keep the message queued and retry. Your server gives up only when its queue lifetime runs out (5 days by default in Postfix), and then sends you a bounce that quotes the last 4.2.2 reply.

Reply Meaning What your server does
452 4.2.2 Mailbox full, try later Retries until the queue lifetime ends
552 5.2.2 Mailbox full, refused Bounces now
552 5.3.4 Message too big for the system Bounces now; the mailbox may be fine

Some older servers send 552 for an oversized message too. If the bounce mentions size, it is a message limit, not a full mailbox.

Common causes

  • The recipient really is out of space: years of attachments, or a shared storage quota (Google accounts share storage across Gmail, Drive and Photos).
  • An abandoned mailbox nobody reads, which fills up with spam until it rejects everything.
  • A low quota set by the hosting plan or admin.
  • A large attachment pushing a nearly full mailbox over the limit, while smaller messages still get through.

What to do as a sender

  1. Tell the recipient another way. Only they or their admin can free space.
  2. Resend later, ideally without large attachments; share a link instead.
  3. On mailing lists, treat repeated full-mailbox bounces as soft bounces and suppress the address after several. An abandoned mailbox will never empty.

What to do as the mailbox owner

  1. Delete large messages and empty Trash and Spam (some providers count them against the quota).
  2. Raise the quota or buy more storage.
  3. On a self-hosted server, check the quota settings. With Dovecot, for example:
doveadm quota get -u john@example.com
doveadm quota recalc -u john@example.com

# dovecot.conf (quota plugin)
plugin {
  quota_rule = *:storage=5G
}
  1. If an address is not used any more, delete it or turn it into an alias, so senders get a clear 550 5.1.1 instead.

To see which server produced the bounce and when, paste it into the Email Header Analyzer.

  • 550 5.1.1: the address does not exist at all.
  • 550 5.7.1: refused for policy reasons.
  • 421 4.7.28: another temporary deferral, for sending rate.

Check the recipient domain's mail servers with the DNS Lookup, or your own domain's setup with the Email Checker.