To be able to disable the notification of the maximum email limit reached per hour, you must eliminate the restriction either at the account level or at the server level, as indicated above, for this you must have access to WHM as an administrator.
Disabling this hourly email limit restriction may have the disadvantage that in the event that an account is compromised and used for mass mailing, the emails that will be sent will be unlimited, this could cause a bad reputation and blocking and adding to the blacklist. .
Mailman is not limited by this restriction.