Despite the popularity of its name, “Contact form 7” with millions of active installations, numerous plugin users have called out the error when hitting the submit button on the form. The error seems to be occurred by change of environment such as migration of the website. Here’s the solution how this can be resolved.

• Go to the WP Admin (Backend) -> Plugins -> Plugin File Editor.
• Select plugin to edit dropdown to select Contact Form 7 and select the file, wp-contact-form-7.php
• On line 30 (the number can be different) after ‘WPCF7_LOAD_JS’, change true to false

Change of code in “Contact form 7” plugin

if ( ! defined( 'WPCF7_LOAD_JS' ) ) {
	define( 'WPCF7_LOAD_JS', false );
}