Hello Selina,

Thank you for reaching out, and I am happy to help!
Yes, the wp-cron is required for the webp to work as expected, as it’s sending requests for the conversion
The W3 Total Cache settings may rely on wp-cron so can you please check with your hosting provider if wp-cron is disabled by any chance?
Check your wp-config.php and check if there is a line: define(‘DISABLE_WP_CRON’, true) ;

Let me know if this is the case
Thanks!