The mailbox cannot receive mail right now — it may be temporarily disabled, receiving too much mail, or rate limited.
Soft bounce · temporary
Common causes
- The recipient receives an unusually high amount of mail
- Temporary account restrictions
How to fix it
- Let your server retry
- If it repeats for days, contact the recipient another way
Bounce ExplainerRun the right check for your domain or paste the full bounce message for a precise explanation.
Open Bounce Explainer →Frequently asked questions
Do I need to resend a 450 message?
No, mail servers retry 4xx errors automatically.