[WP Smush Pro] 500 error smush API

I'm seeing this happening on a few sites hosted on different platforms. The image files seem fine. If I download one of the images and take it to a service like Tinypng it will compress fine. I've tried manually smushing the images and get the same error. This is one of the images that causes the error:

Attachment Page:
https://bouncephysio.healthcaresites.com.au/service/rehabilitative-exercises/manual-therapy-2/

Original Image:
https://bouncephysio.healthcaresites.com.au/wp-content/uploads/2016/06/manual-therapy.jpg