Docker on Synology NAS cannot browse music libreary

[ygi]

Hi,
I have just changed my old Readynas with a synology 1819+ (DSM 6.2.3-25426).
I have installed apnar/logitechMediaServer on the docker application on DSM.
I have mapped the volume share on /music.
But When I go on the lms siteweb (nas:9000) and configure the installation, When I open the browser dialog, the directory music is not listed. But When I go in the terminal (bash) i can get in the mapped directory. I have also tried to edit the server prefs in order to set the right directory. Even if i can see the modifications in the setting page, it cannot scan the library.
Have you an idee what could be the problem ?

I am unable to insert image here.. here are the link to what I tried to describe
https://www.dropbox.com/s/2g03yxkun9je67e/LMS-1.jpg
https://www.dropbox.com/s/2g03yxkun9je67e/LMS-2.jpg

thank you for your help

yves