What it looks like in your logs
552-5.2.2 The email account that you tried to reach is over quota. Please direct the recipient to https://support.google.com/mail/?p=OverQuotaPerm - gsmtpWhat does 5.2.2 mean?
RFC 3463 defines X.2.2 as mailbox full: the mailbox has exceeded its storage limit. The leading 5 makes this reply permanent for this delivery attempt, so the receiving server will not accept the message now. The condition itself can change, though, because the recipient may delete mail or buy more storage. So the bounce is final for this message, but the address may work again next week.
That is why many ESPs treat 5.2.2 as a soft bounce despite the class digit. The sensible approach is to keep sending on your normal schedule and suppress only if the same address keeps returning 5.2.2 across several sends over a week or more. A mailbox that stays full for weeks is usually abandoned, and abandoned mailboxes are how providers recycle addresses into spam traps.
Gmail returns 552 5.2.2 when a recipient is over quota and points them to a storage help page. Microsoft 365 also uses 5.2.2 for a different problem, "submission quota exceeded", when the sender has hit its own sending limit. Read the text to see which one you have.
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 |
| 5.2.2 | ✓ this code |
Common causes
- The recipient has used all of their storage, often shared with other services.
- The mailbox was abandoned and filled up with unread mail over time.
- Large attachments consumed the remaining quota.
- The organization sets small per-user storage limits.
- At Microsoft, the sending account exceeded its own submission quota.
How to fix 5.2.2
- Do not suppress on the first 5.2.2; keep the address on your list for the next send.
- Suppress after roughly three to five consecutive 5.2.2 bounces spread over several days or sends.
- If Microsoft says "submission quota exceeded", reduce your own sending rate; see the Exchange Online limits and our bulk email best practices.
- For transactional mail such as receipts, notify the recipient through another channel if the message matters.
- Treat long-running full mailboxes as inactive and move them into your sunset policy.
5.2.2 questions
What does bounce code 5.2.2 mailbox full mean?
It means the recipient mailbox has reached its storage limit, so the server refused your message. The address is valid. Once the recipient frees up space, mail will be accepted again, so it is usually retried on your next send rather than suppressed straight away.
Is a mailbox full bounce hard or soft?
Technically a 5.2.2 is a permanent failure for that attempt, but because the condition can clear, most platforms treat it as soft with a limit. The temporary variant, 4.2.2, is explicitly soft. In both cases, suppress after repeated failures over several days.
Does a full mailbox bounce hurt my reputation?
A handful do not. A large share of full-mailbox bounces suggests an old list full of abandoned accounts, and some of those may later become spam traps. Watch the trend, and read our bounce rate guide for thresholds. A sudden jump usually points to a specific old segment worth reviewing.