You have create a Kickstart configuration file (e.g. kickstart.json.php) which has one of the following problems:
Its first line is not <?php die(); ?> as explained in the Security section of our documentation. This configuration file is insecure; anyone who accesses it can see the password you have set up. As noted, this can be detrimental to the security of your site.
You have set up a password in that file, but it matches the example password from the Security section of our documentation. As explained on that page, Kickstart will REFUSE to operate when you are using this well-known password; this password offers no security, as everyone knows it! Please use a different password.
Edit your Kickstart configuration file to address this issue.