552 5.3.4 Your message exceeded Google's message size limits
The message is larger than the server accepts
Seen in Gmail, Postfix (Message size exceeds fixed limit), most mail servers
The message, including attachments, is bigger than the receiving (or sending) server allows.
Common causes
- Large attachments: Gmail accepts up to about 25 MB of attachments, and other servers often less.
- Base64 encoding makes attachments roughly a third larger than the files themselves.
- A low message_size_limit on your own Postfix server.
How to fix it
- Share large files as a link (Drive, OneDrive, Dropbox) instead of attaching them.
- Compress or resize attachments before sending.
- If your own Postfix rejects it, raise message_size_limit in main.cf and reload.
Got a different message? Paste it into the error explainer.
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