452 4.5.3: too many recipients
Your message lists more recipients than Gmail accepts at once, so the extra recipients are deferred and need to go in a separate transaction.
- Gmail
- Provider
- Temporary (4xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 452 4.5.3
- Provider
- Gmail and Google Workspace
- Temporary or permanent
- TemporaryThe sending server keeps the message and tries again later.
- Who has to act
- The sender. The fix is on the sending side: your domain, your server or your list.
- What the server says
452 4.5.3 Your message has too many recipients.
What it means
Gmail caps the number of recipients it takes for a single message, and Google links this reply to its page on limits for sending and getting email. For the Workspace SMTP relay, Google's relay documentation gives the number: smtp-relay.gmail.com takes up to 100 recipients per SMTP transaction, and more need another transaction, opened with a new connection or an RSET command. Because the reply is temporary, a well-behaved mail server retries the deferred recipients in a new transaction. Large announcements are better sent through a Google Group, a mailing list or a sending service than as one message with a long To or Bcc line.
Common causes
- A single message with a long list of To, Cc or Bcc recipients.
- Relay traffic through smtp-relay.gmail.com with more than 100 recipients in one transaction.
- Sending software that does not split large recipient lists.
How to fix it
- 01Split the recipient list so each transaction stays within the limit; for smtp-relay.gmail.com that is 100 recipients.
- 02Start a new transaction for the next batch, with a new connection or an RSET command.
- 03For regular large sends, use a Google Group, a mailing list or a dedicated sending service.
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
- SMTP relay service error messages (Google Workspace Admin Help)knowledge.workspace.google.com
Related codes
- 550 5.5.3Too many recipients for this sender.Gmail refused further recipients because this sender has gone over the number of recipients Gmail will accept from it.
- 452 4.5.3Recipient needs its own transaction.The receiving domain's policy settings mean Gmail cannot take this recipient in the same transaction as the others, so it asks you to retry it separately.
- 452Insufficient system storage.The receiving server is short of storage or has hit a limit, such as the number of recipients in one message, and asks the sender to try again later.
- 4.5.3Too many recipients.The message lists more recipients than the server accepts in one transaction; the remaining recipients have to be sent in a separate transaction.
4.5.3 at other providers
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