By default postfix limits the attachment size to about 10 MB. You can determine the current limit with the following command:
# sudo postconf | grep message_size_limit message_size_limit = 10240000 |
To increase the limit add (or change) the following setting in the file /etc/postfix/main.cf:
# 20MB message_size_limit = 20480000 |
After restarting the postfix service the new limit will be active:
# sudo service postfix restart |
