Now I am feeling a bit dumb.
I bought a Raspberry Pi 4 and moved Volumio from my NUC to the RPi.
I had no problem either mounting my NAS for the main library or installing the DLNA plug-in. However, when I try to mount the same NAS as the DLNA server database mount, I get the error message that the audio files directory does not exist.
The IP address for the NAS is 192.168.0.10. The network share for the music files is \medianas\music. The main library mount is \192.168.0.10\music.
I have tried both \medianas\music and 192.168.0.10\music, as well as just \medianas and \192.168.0.10, and I get the same error message every time.
Volumio shows up as a DLNA server in the control software, but the library is 0 files. When I first installed the miniDLNA plugin on the NUC, I had no problem mounting the drive as the DLNA library and populating it.
Have you any thoughts about what I might be doing incorrectly? Thank you for your help.