Roon Server not visible from Synology NAS

Hi everybody,

May I did a mistake, but I think somebody is using a DS-216II+ as RoonServer. I’ve been extending the RAM to 8 Gb and pluging an external SSD with the convenient “RoonServer” folder on it. Installed the SPK (and also tried the beta one). But when I look from the remote I see :


This choice is never usuable and disappears in about 15 secondes.
Is there something I can do to win the battle ? Opening some ports ? A specific tuning ?
Thanks.