Bounce Codes
452 4.2.2 Temporary Failure Mailbox full (over quota, temporary)
The recipient's mailbox has exceeded its storage limit and is temporarily refusing new mail until space is freed up.
Common causes
- Recipient hasn't checked or cleaned up their inbox in a long time.
- Abandoned mailbox that's no longer actively monitored.
What to do
Retry later. An address that returns this code repeatedly over an extended period (weeks to months) is a strong candidate for being effectively abandoned, even though the formal response remains "temporary."
FAQ
Should a persistently full mailbox be suppressed?
Many senders apply a policy of converting repeated 452 responses into a suppression after a set number of consecutive occurrences, treating chronic unavailability similarly to a hard bounce.
Catch These Before You Send
100 free credits — work email application after signup, no card required.
Sign up