[Plugin: NextGEN Gallery] Slideshow suddenly malfunctioned

Hello,
Sorry for my bad english.
Uploading images i have a message :”a failure occured” but images are uploaded and visible in my admin but not on my website. Scroll gallery works well, it can find the images. When i go to the overview of nextgen and i check the plugin compatibility it failed, even whith all other plugins disconected and with the default wp theme. You have an example of the problem at this page: https://cultivetonciel.com/nos-ateliers-cerf-volant/atelier-collectif/
I use nextgen for 3 years and i don’t want to give it up. Please help me.

https://www.ads-software.com/extend/plugins/nextgen-gallery/