avwp-redirect-on-fail-link-filter.php

<?php
/**
 * Age Verification - Redirect on fail
 * 
 * @param string $url - The full URL to redirect to (include https://)
 * 
 * @return string
 */
function acme_redirect_on_fail_link( $url ) {
  $url = 'YOUR_NEW_URL_HERE';

  return $url;
}
add_filter( 'avwp_redirect_on_fail_link', 'acme_redirect_on_fail_link' );

Request to update line 9 to 'return $url' to match varibale set in order to work properly