By menu Gravity Forms --> Custom Validation --> Settings you may open the plugin setting page.
Enable save blocked form data
The plugin will block users submitting if the fill in data doesn't match rules that applied to a field so it won't have entry be created in Gravity Forms. Sometime the administrators want to know what data entered by users so this feature will help them.
With this set to yes, the plugin will save the form data every time when users input doesn't match rule that applied to a field. To view the blocked form data, please open the menu of Gravity Forms --> Custom Validation --> Blocked form data
Here is the global settings and you may set this option for individual form on form settings page.
Enable notify administrators
With this option set to yers, then the blocked form data will be sent to administrator's email address( multiple email addresses supported ). You may also edit email body content.
Here is the global settings and you may set enable or disable option and email address(es) for individual form on form settings page.