WP Smush os not compressing images automatically when set to async

The automatic compressing option is not compressing images with async method.

When it's set to asynchronous, it never automatically optimizes images. I had to add define("WP_SMUSH_ASYNC", false); to wp-config to make it work.

Please advise, we need the automatic image optimization along with async method.

Credentials provided in chat.

Please, before making any changes to anything other than the smush plugin mention it to me.