wp smush freezing during smushing

I've let wp smush run for about 9 hours on a sixe that has 635 images that need to be smushed and it still shows the following same screen:

Smush in Bulk

Please be aware, smushing a large number of images can take a while depending on your server and network speed. You must keep this page open while the bulk smush is processing, but you can leave at any time and come back to continue where it left off.

Reduced by 9.9 KB ( 9.74% )
1 of 635 total attachments have been smushed

Smushing in Progress

The number has not moved up at all. The site url is:

I have enabled support access.