Why can MPD not play every .mp3 song?

[kreativnix]

I have a lot of .mp3-music, mostly rendered with k3b and more and more from Amazon as mp3 downloads.
I have compared the ID3-tags with EXIFTOOL and have found no significant difference. What could be the reason that MPD play some titles and some not?
id3krall.txt

[MaxKellermann]

https://www.musicpd.org/help/

[kreativnix]

if I want to
mpd --stderr --no-daemon --verbose
have I first to type
systemctl disable mpd
because only stopping means
"exception: Failed to bind to '/run/mpd/socket'; Failed to bind socket: Address already in use"

thank you for your immediate answer!

[borine]

"exception: Failed to bind to '/run/mpd/socket'; Failed to bind socket: Address already in use"

That error means that you have the mpd socket unit enabled. You should also stop that unit if you want to temporarily run mpd outside of systemd control:

systemctl stop mpd.socket
systemctl stop mpd.service

That way there is no need to disable them. To restart you just need

systemctl start mpd.socket

Then mpd will start automatically when the first client connects.

[kreativnix]

After
systemctl stop mpd.socket
systemctl stop mpd.service
was
mpd --stderr --no-daemon --verbose
not possible because
Failed to bind to '0.0.0.0:6600'; Failed to bind socket: Address already in use

To my origin topic: MPD does not only not play some .mp3 but also some .flac which I made
by converting theese .mp3 with ffmpeg.
(ffmpeg -i "$1" -sample_fmt s16 -vsync 2 "$2")

[kreativnix]

The reason why my Amazon Music Download not could be played were easily the file access rights.
Unfortunately I realized very late that the Amazon files have 700 acces s rights. And therefore MPD didnt read the files but brought no error message which told me that.

[kreativnix]

The reason why my Amazon Music Download not could be played were easily the file access rights.
Unfortunately I realized very late that the Amazon files have 700 acces s rights. And therefore MPD didnt read the files but brought no error message which told me that.