I am having an issue with WP Smush not bulk smushing

I am having an issue with WP Smush not bulk smushing things...I have gotten up to 211 images smushed (out of about 3500) but I have mostly done it through the free WP Smush and then by hand after I purchased an account. I uninstalled the free plugin and installed the pro one using the dashboard. Any ideas on why it might be stalling? The plugin just spins like it's going to attempt something, but the count of smushed photos never goes up.