NextGEN Gallery not appearing

Yikes! Please help ??

All of a sudden most of my NextGEN galleries are missing! On my Gallery website page ALL short-codes appear and no images: https://www.khartist.com/gallery/.
The NextGEN, however, on my Preview webpages DO appear:
https://www.khartist.com/preview-chinabeach/.

I’ve been reading similar posts with a number of other people, but can’t seem to find a clear answer. Can anyone please help?

Thanks