Documents gallery not working

Hello!
I need to display a list of PDF files with a thumbnail of the first page. I’ve only found the Document Gallery plugin to do this. As it requires imagemagick as a dependency, I have also installed it.
I use WordPress 6.4, Document Gallery 4.4.4 and imagemagick-engine 1.7.8.
In my site admin, everything seems to work fine: I create an image gallery with the Gutenberg block, then I upload PDFs via “Add to Document Gallery”.
But in the end, no files are uploaded.
No php errors in the logs.

Thanks for your help.

Marc