Multi-site network and NGG gallery

I have a multi-site network (2 sites) NGG gallery latest version is working fine on the primary site but I can’t create any gallery on the sub-site. This sub-site is in a sub-folder. https://www.juliecloutier.com/mylene is the main site https://www.juliecloutier.com/mylene/galerie-photos/
the gallery is working there.

But on the sub-site https://www.juliecloutier.com/mylene/en

I am unable to create a gallery.

I have verify the option and the gallery paths is good wp-content/blogs.dir/2/files/

When I try to create a gallery it creates a folder in the path folder on the ftp but it does not show as an available gallery in NGG gallery.

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

For me what would really be best is to be able to point both sites on the same path folder to prevent me from duplicating all Gallery, since they should be the same on both sites. Any idea how to do that ? I was unable to modify the gallery path under the NGG gallery option.