Run the following commands as root on cPanel server.
Block :
whmapi1 suspend_outgoing_email user=USERNAME
Unblock :
whmapi1 unsuspend_outgoing_email user=USERNAME
November 8, 2019
How to block a cPanel user from sending spam/email
September 19, 2009
cPanel/WHM max emails each domain can send per hour
if you want to limit all domains globally , login into your WHM control panel. then go to Server Configuration –> Tweak Settings.
in the Mail section , you will find this setting :
The maximum each domain can send out per hour (0 is unlimited)
set it to any number that you want and click on Save.
but if you want to set the limit for each domain individually , edit /var/cpanel/maxemails :
nano /var/cpanel/maxemails
and add the following line into it ( replace domain.com and 100 with your domain name and limit number ) :
domain.com=100
then execute the following command :
/scripts/build_maxemails_config