You may receive an alert stating the following.
FAILED: Found some nonexistent user's packages.
This alert occurs when some cPanel accounts are assigned non-existent packages.
Assign all accounts to currently existing packages, or recreate the missing packages.
You can change the package for an account in the following location in WHM.
Home » Account Functions » Upgrade/Downgrade an Account
You can create a package in the following location of WHM.
Home » Packages » Add a Package