[BUG] mbsync reports "Release ID not found" in container

[jimbo27]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

Using beet mbsync -p artist:"Iron Maiden" album:"Killers" inside container shows:
mbsync: Release ID c270fee9-894e-49c3-9d10-3f8455e3791d not found for album Iron Maiden - Killers

Expected Behavior

The MBID is available at musicbrainz.org:
https://musicbrainz.org/release/c270fee9-894e-49c3-9d10-3f8455e3791d
The album was correctly imported in the past and should be found with mbsync.
The error also affects other artists/albums.

Steps To Reproduce

Enter beet mbsync -p <any present artist/album>

Environment

- OS: Debian 12 (Bookworm)
- How docker service was installed: OpenMediaVault

CPU architecture

x86-64

Docker creation

services:
  beets:
    image: linuxserver/beets:latest
    container_name: beets
    environment:
      - PUID=1004
      - PGID=100
      - TZ=Europe/Berlin
    volumes:
      - /var/docker/beets:/config
      - /srv/dev-disk-by-uuid-***/music:/music
      - /srv/dev-disk-by-uuid-***/download/music:/downloads
    ports:
      - 8337:8337
    restart: unless-stopped
    network_mode: bridge

Container logs

beets  | [migrations] started
beets  | [migrations] no migrations found
beets  | usermod: no changes
beets  | ───────────────────────────────────────
beets  | 
beets  |       ██╗     ███████╗██╗ ██████╗
beets  |       ██║     ██╔════╝██║██╔═══██╗
beets  |       ██║     ███████╗██║██║   ██║
beets  |       ██║     ╚════██║██║██║   ██║
beets  |       ███████╗███████║██║╚██████╔╝
beets  |       ╚══════╝╚══════╝╚═╝ ╚═════╝
beets  | 
beets  |    Brought to you by linuxserver.io
beets  | ───────────────────────────────────────
beets  | 
beets  | To support LSIO projects visit:
beets  | https://www.linuxserver.io/donate/
beets  | 
beets  | ───────────────────────────────────────
beets  | GID/UID
beets  | ───────────────────────────────────────
beets  | 
beets  | User UID:    1004
beets  | User GID:    100
beets  | ───────────────────────────────────────
beets  | Linuxserver.io version: 2.5.1-ls293
beets  | Build-date: 2025-10-14T23:07:37+00:00
beets  | ───────────────────────────────────────
beets  |     
beets  | [custom-init] No custom files found, skipping...
beets  |  * Serving Flask app 'beetsplug.web'
beets  |  * Debug mode: off
beets  | WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead.
beets  |  * Running on http://127.0.0.1:8337
beets  | Press CTRL+C to quit
beets  | Connection to localhost (127.0.0.1) 8337 port [tcp/*] succeeded!
beets  | [ls.io-init] done.

[github-actions]

Thanks for opening your first issue here! Be sure to follow the relevant issue templates, or risk having this issue marked as invalid.

[mtrolley]

There was a breaking change in beets release 2.4.0 which moved the musicbrainz tagger to a separate plugin which must be added to your plugins: https://beets.readthedocs.io/en/stable/changelog.html#september-13-2025

If no plugins are in your config, the musicbrainz plugin is loaded by default, but if you do you have plugins defined in your config and don't include musicbrainz it is not loaded.

I just got caught by this myself.

[jimbo27]

The plugins are defined in my config.yaml file.
I added musicbrainz and restarted beets. Now the prompt works with mbsync.

Thanks for the hint!