Please make a copy of configuration files before editing the same.

Steps:

Go to the following file and add the domain name.

/var/cpanel/maxemails

Eg:example.com = 1000

Just add an entry like example.com = 1000 . Now 1000 will be the maximum email per hour limit for domain.

Execute the following script after updating the file /var/cpanel/maxemails, this will update the email settings in cpanel database.

#/scripts/build_maxemails_config

If you require help, contact SupportPRO Server Admin