logo

Email error 552 5.2.2: Mailbox full (over quota)

The recipient mailbox exists but has reached its storage limit and cannot accept new mail right now. It is often treated as temporary, but it can last for weeks.

Temporary failure (soft bounce)

What it means

The recipient mailbox exists but has reached its storage limit and cannot accept new mail right now. It is often treated as temporary, but it can last for weeks.

Common causes

  • The person has not cleaned the mailbox for a long time.
  • The mailbox is unused or abandoned and keeps filling up.
  • A shared or role mailbox has a small quota.
  • Large attachments used up the space.

How to fix it

  1. Retry later; many servers keep trying for a few days.
  2. If the same address keeps returning this error, stop sending to it.
  3. Contact the person by another channel if the message is important.
  4. Do not delete it from your records as invalid: the address is real.

How to prevent it

Most bounces come from addresses that were never checked. Verify each address before you send: syntax, domain, mailbox and risk are checked without sending a message. Test a single address with the free email checker or upload a whole list for bulk verification.

Verify an email address free · Clean a whole list · MX lookup · SPF, DKIM and DMARC checker

Frequently asked questions

Is a full mailbox a hard or soft bounce?

Usually soft: the address is valid but cannot receive mail at that moment.

When should I stop sending?

After a few repeated failures over several campaigns, treat the address as inactive.

Other error codes

550 5.1.1User unknown (mailbox does not exist) 550 5.7.1Message rejected by policy (blocked) 550 5.7.26Sender not authenticated (SPF/DKIM/DMARC) 550 5.4.1Recipient address rejected: access denied 553 5.1.3Invalid address syntax 554 5.7.1Transaction failed: service unavailable or blocked

All email error codes