Hey!
I had a really good config on raspberry pi 3 a years ago, with working minidlna on it. And after somethings I decided to reinstal it from the begining. And everythings went good except the instalation/configuration of minidlna. After a few tries i left it, i thought the repo contains somekind of bad program.
But today I also gave it a try, and i still cant make it work good.
The problem is came after i change the music/video directory to my mountig stuffs. The minidlnad status says it failed to start; and minidlna-r says root@PiMediaServer:~# minidlnad -R
[2017/06/04 12:34:17] minidlna.c:586: fatal: Media directory entry not understood [“M”,/mnt/KulsoWinyo/Zene]
And I thing it’s in correct form, so please anybody who knows what is the problem with my config file, give some suggestion to me 
This folder is existing, I use this every hour with samba, so i really dont know what to do 
# WARNING: After changing this option, you need to rebuild the database. Either
# run minidlna with the '-R' option, or delete the 'files.db' file
# from the db_dir directory (see below).
# On Debian, you can run, as root, 'service minidlna force-reload' instead.
media_dir=M,/mnt/KulsoWinyo/Zene/
media_dir=V,/mnt/KulsoWinyo/Filmek/
media_dir=V,/mnt/KulsoWinyo/Letöltések/
# Path to the directory that should hold the database and album art cache.
db_dir=/mnt/dietpi_userdata/.MiniDLNA_Cache
# Path to the directory that should hold the log file.
log_dir=/var/log
# Must be one of "off", "fatal", "error", "warn", "info" or "debug".
# "off" turns of logging entirely, "fatal" is the highest level of importance
log_level=warn
# Use a different container as the root of the directory tree presented to
# clients. The possible values are:
# * "." - standard container
# * "B" - "Browse Directory"
# * "M" - "Music"
# * "P" - "Pictures"
# * "V" - "Video"
# if you specify "B" and client device is audio-only then "Music/Folders" will be used as root
#root_container=.
# Network interface(s) to bind to (e.g. eth0), comma delimited.
#network_interface=eth0,wlan0
# IPv4 address to listen on (e.g. 192.0.2.1).
#listening_ip=
# Port number for HTTP traffic (descriptions, SOAP, media transfer).
port=8200
# URL presented to clients.
# The default is the IP address of the server on port 80.
#presentation_url=http://dietpi:80/minidlna
# Name that the DLNA server presents to clients.
friendly_name=PiMediaServer MiniDLNA
# Serial number the server reports to clients.
serial=12345678
# Model name the server reports to clients.
#model_name=Windows Media Connect compatible (MiniDLNA)
# Model number the server reports to clients.
model_number=1
# Automatic discovery of new files in the media_dir directory.
inotify=yes
# List of file names to look for when searching for album art. Names should be
# delimited with a forward slash ("/").
album_art_names=Cover.jpg/cover.jpg/AlbumArtSmall.jpg/albumartsmall.jpg/AlbumArt.jpg/albumart.jpg/Album.jpg/album.jpg/Folder.jpg/folder.jpg/Thumb.jpg/thumb.jpg
# Strictly adhere to DLNA standards.
# This allows server-side downscaling of very large JPEG images, which may
# decrease JPEG serving performance on (at least) Sony DLNA products.
#strict_dlna=no
# Support for streaming .jpg and .mp3 files to a TiVo supporting HMO.
#enable_tivo=no
# Notify interval, in seconds.
notify_interval=32415
# Path to the MiniSSDPd socket, for MiniSSDPd support.
#minissdpdsocket=/run/minissdpd.sock
