4.2.2
Enhanced Status Code 4.2.2: Mailbox Full - Temporary
Temporary failure
Medium severity
Mailbox
RFC 3463
What it means
Enhanced Status Code 4.2.2 means “Mailbox Full - Temporary.” The recipient mailbox is temporarily over quota. The server is indicating this is a temporary condition and suggests retrying later. This is the soft bounce variant of the mailbox full error.
At a glance
Code4.2.2
Bounce typeSoft (temporary)
SeverityMedium
CategoryMailbox
What to doQueued and retried automatically
StandardRFC 3463
452 4.2.2 The email account that you tried to reach is over quota. Please direct the recipient to https://support.google.com/mail/?p=OverQuotaTemp - gsmtpWhat does 4.2.2 mean?
Enhanced status code 4.2.2 is the explicitly temporary version of the mailbox full error. While 5.2.2 is technically permanent but often treated as temporary, 4.2.2 clearly signals that the server expects the condition to be resolved and the message should be retried.
Your sending server should automatically retry delivery. However, the same best practices apply as with 5.2.2 - suppress the address after multiple consecutive failures over several days to maintain good list hygiene.
How 4.2.2 plays out
Your server attempts delivery
The recipient defers with a temporary
4.2.2 replyYour server queues the message and retries on a back-off schedule
It delivers on a later attempt, or becomes a hard bounce if it keeps failing
Where 4.2.2 sits: soft vs hard bounce
| Soft bounce (4xx) | Hard bounce (5xx) | |
|---|---|---|
| Nature | Temporary | Permanent |
| SMTP class | 4xx | 5xx |
| What to do | Let it retry | Suppress the address |
| Recoverable? | Often | No |
| 4.2.2 is | ✓ this code |
Common causes of 4.2.2
- Recipient mailbox is at storage capacity
- Temporary storage allocation exceeded
- Mailbox cleanup expected by the server
How to fix 4.2.2
- Allow automatic retries - your MTA should handle this
- Suppress after 3-5 consecutive failures over multiple days
- Contact recipient through alternative channel if time-sensitive
Frequently asked questions
What does bounce code 4.2.2 "Mailbox full" mean?
Bounce code 4.2.2 means the recipient's email account has exceeded its storage quota and cannot accept new messages. This is a temporary (soft) bounce; the email was not delivered at this moment, but it may succeed later once the recipient frees up space. Your sending server will typically retry delivery automatically over the next 3-5 days.
Is 4.2.2 a soft bounce or hard bounce?
The 4.2.2 error is a soft bounce (temporary failure), indicated by the leading "4." The recipient's mailbox is temporarily unable to accept messages due to being over quota. Unlike hard bounces (5xx), soft bounces can resolve themselves when the recipient deletes emails and frees storage space. However, if the mailbox remains full throughout the retry period, the message will eventually hard bounce.
Does a 4.2.2 bounce hurt my sender reputation?
Isolated 4.2.2 bounces are generally considered minor by mailbox providers like Gmail and do not significantly impact your sender reputation. However, a sustained high rate of 4.2.2 errors across many recipients signals that a large portion of your mailing list is inactive or unengaged, which can negatively affect your reputation. Regularly clean your email list by removing addresses that consistently return over-quota bounces.
How do I fix a 4.2.2 over quota error?
As a sender, you cannot directly fix this error because the recipient's mailbox is full. Your email server will automatically retry delivery. If the message is urgent, contact the recipient through another channel and ask them to delete unnecessary emails, empty their trash folder, and manage their storage. For mailing lists, segment out addresses with repeated 4.2.2 bounces as they likely represent abandoned or inactive accounts.
Related bounce codes
Sources & further reading
Reviewed by Jennifer Jackson, Email Deliverability Analyst · June 2026
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