Why is the mp3 created by ffmpeg not detected by Synology music station or DLNA server?

I have a mp4 video file. I have used the following command to extract the audio in mp3 format.

ffmpeg -n -i video.mp4 -f mp3 -vn /volume1/music/audio.mp3

The mp3 is not detected by the DLNA server on Synology nor is it detected Music app on Mac.

Why is this happening?

If it is helpful I ran ffmprobe on the output file and following is the output.

user1@macpro Downloads % ffprobe audio.mp3
ffprobe version 4.3.1-tessus  https://evermeet.cx/ffmpeg/  Copyright (c) 2007-2020 the FFmpeg developers
  built with Apple clang version 11.0.0 (clang-1100.0.33.17)
  configuration: --cc=/usr/bin/clang --prefix=/opt/ffmpeg --extra-version=tessus --enable-avisynth --enable-fontconfig --enable-gpl --enable-libaom --enable-libass --enable-libbluray --enable-libdav1d --enable-libfreetype --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libmysofa --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvmaf --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-libzmq --enable-libzvbi --enable-version3 --pkg-config-flags=--static --disable-ffplay
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100
Input #0, mp3, from 'audio.mp3':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:04:29.27, start: 0.025057, bitrate: 128 kb/s
    Stream #0:0: Audio: mp3, 44100 Hz, stereo, fltp, 128 kb/s
    Metadata:
      encoder         : Lavc58.91

Solution 1:

Same problem here (In itunes Music). My problem was that Itunes Music absolutely refused to sort one audio file into the correct Album Folder. I checked all id3 tags, no change made any difference. At the end of my rope, I tried, (Select File) Then File → Convert→ Create MP3 Version. The created file kept my ID3 Tag presets and suddenly my problem was gone. The original file was created by Lavf58.45.100. This is the only variable I found, tags or otherwise, that evidently caused my problem. It may have something to do with Low-complexity bit-allocation algorithm for MPEG AAC audio coders. Using the method above, this was resolved.The new created file was by Music 13.1.6.37 .