What it looks like in your logs
452-4.2.2 The recipient's inbox is out of storage space. Please direct the recipient to https://support.google.com/mail/?p=OverQuotaTemp - gsmtpWhat does 4.2.2 mean?
Enhanced code 4.2.2 is the temporary form of mailbox full. The recipient has run out of storage and the receiving server is refusing new mail for the moment, but it is signalling that the condition may clear. Your server keeps the message queued and retries, and delivery succeeds if the recipient frees up space in time. Nothing needs to change on your side for that first retry.
Unlike 5.2.2, there is no ambiguity about how to treat 4.2.2: it is a soft bounce. The list hygiene question is how long to wait. A mailbox that is full for a day is a busy person. A mailbox that is full for weeks is abandoned, and abandoned addresses are a spam-trap risk once providers recycle them. Tracking consecutive failures per address is the simplest way to tell the two apart.
Gmail returns 452 4.2.2 with text saying the recipient's inbox is out of storage space and a link to its storage help page. Microsoft 365 and Yahoo usually report full mailboxes with 5.2.2 or a 552 reply instead of 4.2.2. Whichever provider you see it from, the handling is the same: retry, count, and suppress only after a sustained run of failures.
Soft or hard bounce?
| Soft bounce (4xx) | Hard bounce (5xx) | |
|---|---|---|
| Nature | Temporary | Permanent |
| Sender behaviour | Queue and retry with backoff | Stop, suppress the address |
| Reputation risk | Low, unless it repeats for days | High above a 2% bounce rate |
| 4.2.2 | ✓ this code |
Common causes
- The recipient has reached their mailbox storage limit.
- Shared storage with other services, such as cloud files, filled the quota.
- The mailbox is no longer checked and has filled up with unread mail.
- Large attachments used up the remaining space.
How to fix 4.2.2
- Let the MTA retry; many full mailboxes clear within a day or two.
- Keep the address on the list for normal sends and track consecutive soft bounces per address.
- Suppress after roughly three to five consecutive full-mailbox bounces spread over several days.
- For important transactional messages, contact the recipient through another channel.
- Fold long-running soft bouncers into a sunset policy so abandoned addresses leave the list.
4.2.2 questions
What does bounce code 4.2.2 mean?
It means the recipient mailbox is full at the moment and cannot accept your message. It is temporary: your server will retry, and if the recipient clears space the message is delivered. The address itself is valid. No action is needed yet.
Is 4.2.2 a soft bounce or a hard bounce?
It is a soft bounce. The leading 4 marks it as temporary. Do not suppress on the first occurrence. Only suppress if the same address keeps returning mailbox full across several sends over a week or more, which suggests it has been abandoned.
Does a 4.2.2 bounce hurt my sender reputation?
Individually, no. A high share of full-mailbox bounces suggests an aging list with many inactive addresses, and that can correlate with spam traps and weak engagement. Watch the trend and clean your list; see our list hygiene guide. Individual full mailboxes are not a problem on their own.