You can control the email sending limits from the WHM panel itself. The options are there under Home »Server Configuration »Tweak Settings option. You can control it for each of the domains in your WHM panel. You can watch the video tutorial for the same by clicking here. The steps are provided below:
- Log in to the WHM panel as root.
- Go to Server Configuration »Tweak Settings option.
- Select the subsection 'Mail'.
- You can see the different options to control the email activities on the accounts under the panel.
- Once done, press the Save button at the bottom, and you are done.