Hi @junior,
I know this is obvious, but just to be sure, can you please confirm that you are using the latest version of the plugin (2.2.8)?
There was an issue with saving options for a subset of users a couple weeks ago, but that was resolved. I suspect you’re having the same issue. If you are fully up-to-date, and still cannot save, we’d need to troubleshoot. It’s likely to be something specific to your environment as the lightbox, including saving option, is working well for us and most users.
Also to confirm, when you say it ‘will no longer work’, do you mean that saving/updating options is not working, or that the lightbox is not opening images on the front end after you save?