552 5.3.4: Message Too Big for System
The 552 5.3.4 bounce means your message exceeds the receiving mail system's overall size limit. Learn how to reduce email size and fix this bounce.
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552
5.3.4
Message Too Big for System
Very Common
🔢 Enhanced Status Code Breakdown: 5.3.4
| Component | Value | Meaning |
|---|---|---|
| Class | 5 | Permanent failure (Hard bounce) |
| Subject | 3 | Mail system status |
| Detail | 4 | Message Too Big for System |
Per RFC 3463 Enhanced Mail System Status Codes. Class (X) = severity, Subject (Y) = category, Detail (Z) = specific condition.
💬 What This Error Means
This email is too large for the entire mail system you're sending to. While some errors are about a specific person's inbox being full, this one means the 'entry gate' of their company's email system has a strict weight limit that your message exceeded.
Common Causes
- Very large attachments pushing the total message over the system limit
- Lots of high-resolution images embedded directly in the email body
- The company has a very low "system-wide" limit for all incoming mail
- The total size includes the email text, all the technical headers, and the attachments
How to Fix This
- Upload large files to a cloud service (like OneDrive or iCloud) and send a link instead
- Use a "file transfer" service for exceptionally large documents
- Avoid embedding large images directly into the email; host them online and link to them instead
- Try to keep your total email size under 20MB to ensure it reaches most business systems
📚 Official Documentation
Google Workspace has a system-wide 25 MB send limit and 50 MB receive limit. Exceeding these results in 552 5.3.4.
📖 Google Workspace / Gmail documentation → Browse all Google Workspace / Gmail error codes →Microsoft 365 default system limit is 25 MB. Enterprise plans can configure up to 150 MB per organisation.
📖 Microsoft 365 / Outlook documentation → Browse all Microsoft 365 / Outlook error codes →📋 Real-World Example Messages
These are real bounce message formats you might receive. Paste yours into the Bounce Decoder for instant analysis.
552 5.3.4 Message size exceeds fixed maximum message size 552 5.3.4 Message too large
🔗 Related Error Codes
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