This error will show if a Contact Form 7 is used in a Slider Modal:

To fix this, insert the custom JS code below into the slider modal.
jQuery( 'div.wpcf7 > form' ).each( function() {
var $form = jQuery( this );
wpcf7.initForm( $form );
if ( wpcf7.cached ) {
wpcf7.refill( $form );
}
});
Hi KC!
thanks for your great work and support.
I have the same problem – the Ajax zero- with WP Forms.
How do I fix this?
Hi Jochen,
Thanks for your message. We’ve not tested WP Forms yet and could you please drop us an email at [email protected] so that we could investigate this further on your end?
Thanks!
KC
ThemePunch
I had solved the problem of the number “0” some time ago thanks to this code. Everything worked perfectly until yesterday. Unfortunately, without touching anything to the code, the error started recurring again, I don’t know if due to the latest Slider Revolution update. The JS code was entered correctly but the error still occurs.
Hello,
thanks for contacting us! Your request requires one of our support agents to have a closer look.
In order to give our clients the best support possible, we are having a support ticket system reachable via the link below.
Please use it for your upcoming questions concerning one of our products. This will guarantee the fastest answer possible. Support requests here cannot be answered unfortunately. Thank you!
Please use our ticket systems over at:
https://support.sliderrevolution.com
Cheers Dirk @ Slider Revolution
I solved the problem and I write the solution here, hoping it will be useful to those who have encountered the same error. Version 5.4 of Contact Form 7 evidently has some bugs. I solved it by simply downgrading to the previous version.