AJAX Confirmation Redirect doesn't work

On the website of a client we use Gravity Forms, but it seems that since the last update the confirmation redirect is not working anymore.
Whenever one of the forms is being sent an AJAX request is fired and the result is:
<!DOCTYPE html><html><head><meta charset='UTF-8' /></head><body class='GF_AJAX_POSTBACK'><script type="text/javascript">document.addEventListener( "DOMContentLoaded", function() { function gformRedirect(){document.location.href="https:\/\/www.website.extensions\/page-thanks\/";} }, false );</script></body></html>

It looks like it’s trying to attach itself to the page, but nothing is happening.
The installed version of Gravity Forms is 2.4.19 running on Wordpress 5.4.2

Hi Tim. I recommend opening a support ticket for this issue:

https://www.gravityforms.com/open-support-ticket/

Hey Chris,

I can’t contact support because I don’t have access to the account that purchased the license. I got the license key… But no access to the account that bought it. That one belongs to someone else, that’s why I posted here…

Hi Tim. What is the URL of the page on the site where we can see this issue? Thank you.

Hey Chris,

If you go to: https://www.adoor.nl/contact/ and fill in the form it will send the form, but it will not redirect.

Hi Tim. I was able to see the issue with the AJAX submission never showing a confirmation. What happens if you test this form from the Form Preview?

Hi Chris,

When I send the form from the Form Preview it will direct.
It looks like the event is not being executed on the page itself.

If it works in the preview but not in the page, there is likely another script interfering. That can come from a plugin or your theme. Please use these steps to check for theme and plugin conflicts: