WHM/cPanel

You can edit number of emails a user can send from his/her domain per hour. Below are the steps:

1. Edit /var/cpanel/maxemails file through SSH.
2. Add an entry like "domain.com = 100". Now, domain.com will be able to send 100 emails per hour.

Once you perform above steps, do not forgot to execute script /build_maxemails_config.

Thanks!

Scott.