Thumbnails grayed out after migration

I have used your plugin in the past without issues. Loved it.

I installed it on a new site built locally this spring, and the plugin was perfect for the topic. I used the Magnific Popup lightbox. I’m a fan.

I migrated the new site to my host on Monday night, and two things happened. The thumbnails in the galleries became grayed out anywhere I used a gallery (pages, posts, custom posts, even when clicking “View” in the gallery dashboard). And the arrows on the lightbox were no longer there when the lightbox opened.

I made sure that the grayed out photos actually made the migration and were where they were supposed to be. I double-checked that the links matched.

I’ve used different computers and different browsers to check this, so it’s not a browser thing.

I don’t expect you to solve this for me. But could you point me in the right direction? Where would you look if you saw grayed-out thumbnails?

I had to put the site into maintenance mode while I solve this, so I don’t have a link.

Thanks in advance for any guidance.