Immich external library

Hi and thanks for reading this!

I’ve just installed the Immich rockon and have manually uploaded some pictures to it. However, I’d like Immich to get the pictures from a sync’ed backup directory I keep inside the Rockstor Server at

RockstorNAS:/mnt2/backup_Gentoo_casa/Ramilene_fotos

The directory /mnt2/backup_Gentoo_casa/ is the Rockstor backup of my Linux local box and contains these subdirectories:
RockstorNAS:/mnt2/backup_Gentoo_casa # ls -la
total 0
drwxr-xr-x 1 999 root 42 feb 7 20:32 .
drwxr-xr-x 1 root root 284 feb 7 13:43 ..
drwxr-xr-x 1 999 root 4872 feb 7 12:30 etc
drwxr-xr-x 1 999 root 96 nov 29 18:47 home
drwxr-xr-x 1 999 root 2248 feb 7 12:23 Ramilene_fotos

When I try to add /mnt2/backup_Gentoo_casa/Ramilene_fotos as an external library through Rockstor’s WebUI for Immich (Add Storage button), I have to choose the “Storage” from the menu, where “backup_Gentoo_casa” is an option (I can’t specify the Ramilene_fotos subdirectory), and also the directory, like “/data/Ramilene_fotos”, where it will be mounted inside the rockon. But after that, when I start Immich again, create an external library through Immich’s settings and set /data/Ramilene_fotos as the folder, I get an error. What’s more, I get 4 equal instances listed of the failing share under Immich Settings in Rockstor.

So, how can I add the subdirectory /mnt2/backup_Gentoo_casa/Ramilene_fotos as the source for an external library configured in the Immich rockon?