Document tree not loading on Space dashboard

On all pages of XWiki 7.4, document trees or trees are not loading space level items. The trees show spaces names but when someone clicks on the arrow to expand a lower level, nothing happens but loading sign. I put a capture of my screen showing the behavior when opening freshly created space dashboard (with two empty pages added) and clicking on title expand. In general, all tree or document tree on each space are not able to print anything but a loading icon.