Can't send email with large attachments

Can’t send email with large attachments. Attachment was 8.2mb.

Got this message when emailing within my own domain (on VM server) from my own email address to another user on our domain. See below:

This message could not be sent because its size exceeded the server’s limit. You can use the option, located in Tools | Accounts | Properties | Advanced, to break messages into smaller parts.

Subject ‘did I send you this already?’
Server Error: 552
Server Response: 552 5.3.4 Error: message file too big
Server: ‘’
Windows Live Mail Error ID: 0x800CCC6D
Protocol: SMTP
Port: 25
Secure(SSL): No

All users have unlimited disk quota. I have a ton of disk space. Any Ideas??


Yeah, Postfix has a default max message size that may be smaller than the email you’re trying to send.

To change the max message size, go into Webmin -> Servers -> Postfix -> General Resource Control, and set “Max size of a message” to your desired max message size.