icons/images in the avia layout builder are missing

I’m not quite sure what happened, as I don’t recall anything changing on the site, but when I logged in today and went to edit a page, in the avia layout builder, all of the images in the avia toolbar are missing. Layout Elements, Content Elements, Media Elements, Plugin Additions… they all show boxes with broken images in them instead of the icons for the feature.

Likewise, within the page layout, all the frames of what I’ve moved into place are there, but none of the icons are there (e.g. the X to close an open frame, or to edit or duplicate a frame. It’s like suddenly the theme can’t find the images.

I went into the file structure to be sure they were there, and they were. I even reinstalled the theme, but that didn’t work. They were working just 2 days ago when I last edited the site, and I did nothing on the site since then.

Can someone please help?
Thank you.