Musicbrainz incorrect query syntax bug leading to 400 Bad Gateway

[night199uk 0]

Just added some new music to my Emby server for the first time in a while; and it seems that Emby is incorrectly formatting the MB query string.

It is duplicating the MBIDs when formatting the query URL.

This is the same for all query types: artists, releases, etc.
Latest MusicBrainz plugin (1.0.0.27 or something) on Emby 4.9.3.0.

In the first case you can see the MB artist ID should be: ba0d6274-db14-4ef5-b28d-657ebde1a396 but it is duplicated in the query string.

Let me know if you need any more debug.

```

2026-03-01 19:00:03.424 Info HttpClient: GET https://musicbrainz.emby.tv/ws/2/artist/ba0d6274-db14-4ef5-b28d-657ebde1a396ba0d6274-db14-4ef5-b28d-657ebde1a396?inc=url-rels
2026-03-01 19:00:03.604 Info HttpClient: Http response 400 from https://musicbrainz.emby.tv/ws/2/artist/ba0d6274-db14-4ef5-b28d-657ebde1a396ba0d6274-db14-4ef5-b28d-657ebde1a396?inc=url-rels after 180ms
2026-03-01 19:00:03.605 Error App: Error in MusicBrainz
    *** Error Report ***
    Version: 4.9.3.0
2026-03-01 19:00:03.859 Info HttpClient: GET https://musicbrainz.emby.tv/ws/2/release/16e1fb14-b248-4a58-ab5e-050c0a9f044416e1fb14-b248-4a58-ab5e-050c0a9f0444?inc=url-rels
2026-03-01 19:00:04.028 Info HttpClient: Http response 400 from https://musicbrainz.emby.tv/ws/2/release/16e1fb14-b248-4a58-ab5e-050c0a9f044416e1fb14-b248-4a58-ab5e-050c0a9f0444?inc=url-rels after 169ms
2026-03-01 19:00:04.029 Error App: Error in MusicBrainz
    *** Error Report ***
    Version: 4.9.3.0
```

[night199uk 0]

Also happens on the latest beta, also with plugin 1.0.27.0:

2026-03-01 19:34:51.509 Info HttpClient: Http response 400 from https://musicbrainz.emby.tv/ws/2/release/549b4b55-01d0-444c-ba13-d817845468bf549b4b55-01d0-444c-ba13-d817845468bf?inc=url-rels after 185ms
2026-03-01 19:34:51.511 Error App: Error in MusicBrainz
	*** Error Report ***
	Version: 4.10.0.4
	Command line: /app/emby/system/EmbyServer.dll -programdata /config -ffdetect /app/emby/bin/ffdetect -ffmpeg /app/emby/bin/ffmpeg -ffprobe /app/emby/bin/ffprobe -restartexitcode 3

[Luke 42107]

Hi there, please attach the Emby server log from when the problem occurred:

How to Report a Problem

Thanks!

 

[Happy2Play 9794]

6 hours ago, night199uk said:

2026-03-01 19:00:03.424 Info HttpClient: GET https://musicbrainz.emby.tv/ws/2/artist/ba0d6274-db14-4ef5-b28d-657ebde1a396ba0d6274-db14-4ef5-b28d-657ebde1a396?inc=url-rels

To me this suggest improperly tagged track.  As it looks like delimiter issue with artist duplicated.

So the question becomes what does ffprobe show for embedded metadata?

 

[night199uk 0]

Hrm. The files were properly tagged - looks like the bug was occurring even for files that haven't changed in years. ffprobe showed correct metadata both for old files and the new files I added. I have used the same beets & picard config a long time with no real changes.

Anyway, I was able to get this to work by upgrading to the 4.10.0.4 beta and then simply doing a complete "Refresh Metadata" on the music library with no other underlying files or configuration changes.

I guess it's probably a latent upgrade bug somewhere... But it's resolved for now and I can't recreate it.