Console error: ajax.response is not defined

[dev4press]

Bug reported on WordPress.org: https://wordpress.org/support/topic/doesnt-work-on-different-sites/.

Uncaught TypeError: ajax.response is undefined
    render https://XXX.com/wp-content/cache/min/1/e49c28530a8eb117585641678850281f.js:227
    init https://XXX.com/wp-content/cache/min/1/e49c28530a8eb117585641678850281f.js:227
    jQuery 5
e49c28530a8eb117585641678850281f.js:227:20840
    render https://XXX.com/wp-content/cache/min/1/e49c28530a8eb117585641678850281f.js:227
    init https://XXX.com/wp-content/cache/min/1/e49c28530a8eb117585641678850281f.js:227
    jQuery 5

[dev4press]

Fixed with: ee68680.