Basic SMTP reply code · RFC 5321
552 Exceeded storage allocation
The action was aborted: the storage allocation was exceeded (a full mailbox or a message too big).
- Class: 5yz · Permanent failure
5yz: a permanent failure. The same request should not be repeated; something must change first, such as the address (RFC 5321 §4.2.1). - Source
How 552 appears at providers
The exact text from the provider's documentation, as you see it in the bounce, and what it means.
Gmail
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552 5.2.2
The recipient's inbox is out of storage space and inactive.
The recipient's mailbox is full and inactive, so the message cannot be delivered.
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552 5.3.4
Your message exceeded Google's message size limits.
The message exceeds Gmail's limits: total size, number of attachments, or the size of the header or of one field in it. Make the message or header smaller.
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552 5.3.4
The number of attachments (num-attachments) exceeds Google's limit of limit attachments.
The message exceeds Gmail's limits: total size, number of attachments, or the size of the header or of one field in it. Make the message or header smaller.
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552 5.3.4
The size of your message (size bytes) exceeded Google's message size limits of limit bytes.
The message exceeds Gmail's limits: total size, number of attachments, or the size of the header or of one field in it. Make the message or header smaller.
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552 5.3.4
Your message exceeded Google's message header size limits.
The message exceeds Gmail's limits: total size, number of attachments, or the size of the header or of one field in it. Make the message or header smaller.
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552 5.3.4
Your message exceeded Google's message header size limits. Messages must not exceed limit total header bytes or limit header fields.
The message exceeds Gmail's limits: total size, number of attachments, or the size of the header or of one field in it. Make the message or header smaller.
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552 5.3.4
The size of the header name header value (size bytes) exceeds Google's limit of limit bytes per individual header size.
The message exceeds Gmail's limits: total size, number of attachments, or the size of the header or of one field in it. Make the message or header smaller.
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552 5.3.4
The size of one of the header values (size bytes) exceeds Google's limit of limit bytes per individual header size.
The message exceeds Gmail's limits: total size, number of attachments, or the size of the header or of one field in it. Make the message or header smaller.
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552 5.3.4
The size of a header name (size bytes) exceeds Google's header name limit of limit bytes.
The message exceeds Gmail's limits: total size, number of attachments, or the size of the header or of one field in it. Make the message or header smaller.
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552 5.3.4
Your message has a Subject: header that exceeds Google's message header size limits.
The message exceeds Gmail's limits: total size, number of attachments, or the size of the header or of one field in it. Make the message or header smaller.
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552 5.7.0
This message was blocked because its content presents a potential security issue.
The message was blocked because its content or an attachment is a potential security issue.
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552 5.7.0
This message was blocked because its content presents a potential security issue.
The message was blocked because its content or an attachment is a potential security issue.
Have the whole error message?
Sources: RFC 5321 · RFC 3463 · RFC 3464 · IANA · Gmail · Microsoft 365 · read on 26 September 2026