Which somehow sounds strange and contradictory to what the package creator wrote on the project’s homepage. Maybe take a backup of your current installation, then delete it and start all over again? Read aslo:
Especially:
The database shared folder can only be set during initial installation. If you’d like to use a different database location, you’ll need to uninstall and install the app again. The uninstallation process does not touch the current database.
To move your database to a new shared folder (or usb/esata volueme), I’d recommend to create a backup within Roon first and restore it when the new database shared folder has been set.
PS: I don’t have Synology and QNAP works a little bit different IIRC. Maybe a Synology user may chime in and be able of more help?