552 5.7.16: too big for its priority
The server limits message size per priority level, and this message is larger than allowed for the priority it was sent with.
- Standard
- Provider
- Permanent (5xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 552 5.7.16
- Provider
- Standard SMTP codes
- Temporary or permanent
- PermanentRefused for good: the message comes back to the sender, and resending it gets the same answer.
- Who has to act
- The sender. The fix is on the sending side: your domain, your server or your list.
- What the server says
552 5.7.16 Message is too big for the specified priority
What it means
Under RFC 6710's priority policy, a server may set smaller maximum sizes for some priority levels. If a message exceeds the limit for its priority, the RFC says the server should reject it with reply code 552 and X.7.16. The registry notes that other 4xx and 5xx codes are allowed and that the condition might be temporary, as when only smaller high-priority messages are accepted for a while. Lowering the priority or shrinking the message gets it through. Separately, the older RFC 4865 (FUTURERELEASE) used X.7.16 for a full per-user quota of messages held for later release, a meaning the registry never recorded.
Common causes
- A large message sent at a priority level with a small size limit.
- Attachments that push the message over the limit for its priority.
How to fix it
- 01Resend at a lower priority, where larger messages may be allowed.
- 02Make the message smaller, or share files by link.
- 03Ask the server's administrator for the size limit at each priority.
Sources
What this page rests on, checked on 20 Oct 2026. The explanation is ours; the reply text is the server's.
Related codes
- 5.7.15Priority too low.The server only accepts messages above a certain transfer priority at the moment, and the priority of this message is below that level.
- 5.3.4Message too big.The message is larger than the maximum size the receiving system accepts for any message, so it was refused and has to be made smaller.
- 552Storage allocation exceeded.The receiving server aborted the message because it exceeded a storage limit, usually a full mailbox or a message larger than allowed.
- 2.3.6Message priority changed.A success code from the MT-PRIORITY extension: the server accepted the message but did not keep the transfer priority the sender asked for.
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