Postfix by default restrict attachment size to approx 10MB i.e. 10240000 bytes.
You can check attachment size it using following command:
postconf | grep message_size_limit
To change attachment size to say 50 MB, run a command like:
postconf -e message_size_limit=52428800
Note: If you are running a mail server with SMTP/IMAP access on it, you only need to change postfix attachment size setting. I spent...
By BIP, February 8, 2016