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552 5.2.2: Mailbox full (permanently)

The recipient is out of storage and the receiver has given up waiting. At Gmail, the account is also inactive.

Bounce type
Hard bounce (permanent)
What to do
Suppress the address
Returned by
Gmail / Google Workspace; Any mail server

What 552 5.2.2 means

5.2.2 is 'Mailbox full'. RFC 3463 intends it as a temporary condition, but many servers send it with a permanent 552 basic code once a mailbox has been over quota for a while. Gmail's 552 5.2.2 says the inbox is 'out of storage space and inactive', which is a clear sign nobody is reading it.

Compare it with 452 4.2.2, which is Gmail's temporary 'out of storage' deferral for an account that's still active.

What the bounce looks like

The wording providers document for this code. Your bounce may add an IP address, a session ID or a help link after it.

Gmail
552 5.2.2 The recipient's inbox is out of storage space and inactive. Please direct the recipient to Manage files in your Google Drive storage.

Why cold emailers see 552 5.2.2

  • An abandoned mailbox that filled up with unread mail.
  • A shared or role address no one maintains.
  • Old addresses in purchased or scraped lists.

How to fix 552 5.2.2

  1. Suppress the address. Nobody is going to read your email there.
  2. If the contact matters, find another way to reach them; they've probably moved to a different address.
  3. Flag the source list. A batch with several inactive mailboxes is old data, and the rest of it deserves re-verification before you send more.

Retry or suppress?

Suppress. A permanent full-mailbox bounce at Gmail means an inactive account, and some mailbox providers use abandoned accounts as spam traps later.

Reading the code

The basic code 552 means "Exceeded storage allocation / message too big (permanent)" under RFC 5321. In 5.2.2, the 5 is the class (permanent failure) and the 2 is the subject (mailbox). The detail number 2 is registered in RFC 3463 / the IANA registry as "Mailbox full".

Class 5
Permanent failure
Resending the same message won't work. Something about the message, the recipient or the sender has to change first.
Subject 2
Mailbox
A problem with the recipient's mailbox, such as full or disabled. Under the recipient's control.
Detail 5.2.2
Mailbox full

Check the rest of your setup

Paste the headers of a message that did get through into the email header analyzer to confirm SPF, DKIM and DMARC pass, and check your domain with the SPF, DKIM & DMARC checker. The deliverability checklist covers the rest of a healthy sending setup.

Got a different bounce? Paste it into the SMTP error code lookup to decode it.

FAQ

Is 552 5.2.2 a hard bounce or a soft bounce?

552 5.2.2 is a permanent failure (a hard bounce): the receiving server won't accept this message if you send it again unchanged. Here the problem is the address itself.

Should I remove the contact after a 552 5.2.2 bounce?

Yes. Suppress. A permanent full-mailbox bounce at Gmail means an inactive account, and some mailbox providers use abandoned accounts as spam traps later.

What does 5.2.2 mean in the error code?

In 5.2.2, the 5 is the class (permanent failure) and the 2 is the subject (mailbox). The detail number 2 is registered in RFC 3463 / the IANA registry as "Mailbox full".

Related SMTP codes

See all SMTP error codes

Sources

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Clement reads the bounces that land in your Gmail and SMTP inboxes and tells dead addresses apart from policy blocks: it suppresses the first across every campaign and keeps the contact on the second, so you don't have to decode bounces by hand.

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