2.3.6: message 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.
- Standard
- Provider
- Success (2xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 2.3.6
- Provider
- Standard SMTP codes
- Temporary or permanent
- SuccessThe server accepted the command or the message.
- Who has to act
- The sender. The fix is on the sending side: your domain, your server or your list.
- What the server says
2.3.6 Requested priority was changed
What it means
RFC 6710 lets a sender ask for a transfer priority on each message. When a server accepts the message but lowers or raises that priority, or the default it implied, it answers with X.3.6, and the text after the code gives the new priority. It is a success code (sent with reply 250 or 251), so the message is on its way and will be handled at a different priority than requested. RFC 6710 was written for settings where priority matters, such as emergency response and military or aviation messaging, so the code is rare elsewhere.
Common causes
- The sender asked for a priority the server does not allow for that sender.
- A site policy that assigns priorities itself, for example by the authenticated user.
How to fix it
- 01No action is needed for delivery: the message was accepted.
- 02Read the new priority in the reply text.
- 03If the original priority must be kept, ask the server's administrator to authorise it for your account.
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.
- 552 5.7.16Too 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.
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