TL;DR
Temporary mailbox over quota: use bounded retry and do not suppress from 4.2.2 alone.
What this code means
X.2.2 means mailbox full. IANA confirmation here is for permanent 5.2.2; this class-4 code rests on exact Gmail 452 evidence.
Provider examples
smtp;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 - gsmtp452 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 - gsmtp<jahid@gmail.com>: host alt1.gmail-smtp-in.l.google.com[124.215.9.62] said: 452-4.2.2 The recipient's inbox is out of storage space. Please direct the 452-4.2.2 recipient to 452 4.2.2 https://support.google.com/mail/?p=OverQuotaTemp q23-20020a50cc97000000b0054ae87c9c39si95693edi.64 - gsmtp (in reply to RCPT TO command)Technical meaning
The documented condition is a mailbox capacity or administrative storage quota exceeded at the attempt.
Delivery status
Class 4 may clear; do not conflate it with permanent 5.2.2.
- Class
- Temporary failure
- Retry
- Controlled retry
- Suppression
- Check the full context
Retry decision
Retry with backoff, jitter, idempotency, and a limit; stop on success, permanent code, or exhaustion.
Suppression decision
Do not suppress from 4.2.2 alone; use a real permanent result or policy.
Common causes
- The recipient mailbox or managed account exceeded its storage allocation.
Diagnostic steps
- Retain the reply; ask the recipient to check usage and an administrator to check quota allocation.
Actions by owner
Sender
- Use bounded retry and share the exact reply if it persists.
Recipient
- Free mailbox space where possible.
Recipient administrator
- Check quota allocation, retention, and state synchronization.
Sources
These sources define what this enhanced status code means, mainly through the IANA registry and related RFCs. When provider examples appear on the page, they come from that provider's published documentation. Follow the links to read the original wording in context.
- RFC 3463 — Enhanced Mail System Status Codes — Defines the class/subject/detail model for enhanced status codes.
- RFC 5248 — A Registry for SMTP Enhanced Mail System Status Codes — Creates and governs the IANA enhanced status code registry.
- Fix bounced or rejected emails — over quota (temporary) — Gmail Help article for the temporary over-quota mailbox condition (452 4.2.2).
- smtp-codes (community corpus) — Community-maintained reference of provider SMTP responses, pinned locally as evidence.
- email-bounce-parser (test fixture corpus) — Open-source bounce-parsing library whose test fixtures are pinned locally as evidence.
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