Is 452 4.2.2 permanent or temporary?

452 4.2.2 is a temporary (4.x.x) failure — a properly configured mail server retries automatically, and the message often delivers on a later attempt. Persistent 452 4.2.2 across recipients points to a deeper issue.

Is this my problem or the recipient's?

Often it resolves itself on retry. If it persists across many recipients, it's usually a sending-side reputation or authentication issue worth fixing.

How do I check my sending setup?

Run a free EmailHealth check on your domain — it verifies SPF, DKIM, DMARC, blacklist status, and more in a couple of seconds, which covers the most common causes of delivery failures.

452 4.2.2 — Mailbox full / over quota

452 4.2.2 is a temporary SMTP reply meaning mailbox full / over quota. 4.2.2 is "mailbox full." It is temporary because the recipient may free up space; your server should retry for a while before giving up.

What 452 4.2.2 means

4.2.2 is "mailbox full." It is temporary because the recipient may free up space; your server should retry for a while before giving up.

ℹ️

This is a 4.x.x temporary failure — a correctly configured mail server retries on a backoff schedule, and the message frequently delivers on a later attempt.

Common causes

📨

The recipient's mailbox is over its storage limit

Most common

The inbox is genuinely full. Nothing on your side is wrong — this is the recipient's problem to resolve.

🔁

An abandoned mailbox that never gets emptied

Common

Inactive accounts fill up and stay full, bouncing 452 4.2.2 on every attempt until they're cleaned or removed.

How to fix 452 4.2.2

1
Let retries run
Your server will retry for a day or more. If the recipient clears space, the message delivers automatically.
2
Contact the recipient another way for important mail
For a critical message, reach the person by phone or chat so they can empty their mailbox.
3
Suppress chronically full mailboxes
If an address returns 4.2.2 on every send for weeks, treat it like a dead address and stop mailing it.

Confirm your domain is set up correctly

Most delivery failures — permanent or temporary — trace back to authentication or reputation. Run a free EmailHealth check to confirm SPF, DKIM, DMARC, blacklist status, and TLS are all healthy for your sending domain. If you send in volume, free daily monitoring will alert you before a small issue becomes a flood of bounces.

Mailbox full / over quota