Step::1 Login to your WHMCS Interface.
Step::2 Navigate to Setup section and click on General settings.
Step::3 Now jump onto the Other section and search for Hooks debug mode option.
Step::4 Enable the Hooks Debug Mode option.
Step::5 Click on Save changes.
Step::6 Now go back to WHMCS Home page and go to Utilities section.
Step::7 Click on Activity log option to display the error.
Step::9 Locate the “Email Send Aborted By Hook” error in the log
Check the video tutorial to know the procedure in detail. You may check out the blog as well.