Can't add new projects to the portfolio

I have two projects in my portfolio, but can’t add any more. Clicking the add project/image button takes me to the media library window. When I select an image and hit the “add image” button, a frozen blank grey screen appears. I’ve deactivated and reactivated the plugin. I’ve deleted the plugin and reinstalled it. I’ve tried different styles and different images. Nothing works. I can’t add any new projects. Please help!

https://test.bbblack.com/portfolio/

https://www.ads-software.com/plugins/portfolio-gallery/