550 5.2.1: recipient receiving too much mail
Gmail permanently rejected your message because the recipient's account is receiving mail faster than Gmail lets it accept.
- Gmail
- Provider
- Permanent (5xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 550 5.2.1
- Provider
- Gmail and Google Workspace
- Temporary or permanent
- PermanentRefused for good: the message comes back to the sender, and resending it gets the same answer.
- Who has to act
- Either side, depending on the cause. Start with the checks below that are yours.
- What the server says
550 5.2.1 The user you are trying to contact is receiving email at a rate that prevents…
What it means
This is the permanent counterpart of 450 4.2.1. The recipient's account is taking in mail at a rate that stops Gmail from delivering more, and this time Gmail returns the message instead of asking for a retry. Google links the reply to its page on limits for sending and getting email. The cause sits with the recipient, whose mailbox is being flooded, perhaps by a loop, a script or a list. You can send the message again later, but resending automatically only adds to the flood.
Common causes
- A mail loop or auto-reply loop sending to the account.
- A large volume of automated or list mail arriving at once.
- Your own system sending many messages to this address in a short time.
How to fix it
- 01Do not resend automatically; wait, then send the message again by hand.
- 02If your system writes to this address often, reduce how many messages it sends and spread them out.
- 03Tell the recipient through another channel so they or their admin can find what is flooding the mailbox.
Sources
What this page rests on, checked on 20 Oct 2026. The explanation is ours; the reply text is the server's.
- Gmail SMTP errors and codes (Google Workspace Admin Help)knowledge.workspace.google.com
Related codes
- 450 4.2.1Recipient is receiving mail too fast.Gmail is holding back your message because the recipient's mailbox is taking in mail faster than Google allows, so your server should try again later.
- 550Mailbox unavailable.The receiving server permanently refused the message for this recipient: the mailbox does not exist, cannot be reached, or the server rejected the message by policy.
Further reading
All 108 Gmail codesEvery code in the wikiPaste your own bounce