Failure to play non-mp3's on default profile (transcoding doesn't kick in?)

[stefaanderoeck]

For my Beoplay M5, playing AAC or VORBIS seems to fail consistently, MP3 works correctly. Judging from the logs, it uses the default profile, but playing results in a "500 (Internal Server Error)". (The GUI does not give any feedback at all, positive or negative)
The same setup plays all files correctly to my Marantz, which is a newer device (that probably supports all codecs), and does not fall back to a default profile.

Jellyfin version: 10.10.3
Dlna plugin: 6.0.0.0

Expected behaviour: Jellyfin to do the required transcoding for the Beoplay M5?

I've included a sniipet from the debug-enabled logs below.
Don't hesitate to indicate if and how I obtain more useful debugging information.

Thanks,
Stefaan

jellyfin  | [09:46:15] [INF] [43] Jellyfin.Plugin.Dlna.DlnaManager: No matching device profile found. The default will need to be used. 
jellyfin  | {"FriendlyName": "Keuken", "ModelNumber": "2.3.54366.192026550", "SerialNumber": null, "ModelName": "Beoplay M5", "ModelDescription": "", "ModelUrl": "www.bang-olufsen.dk", "Manufacturer": "Bang & Olufsen", "ManufacturerUrl": "www.bang-olufsen.dk", "Headers": [], "$type": "DeviceIdentification"}
jellyfin  | [09:46:15] [DBG] [43] Jellyfin.Plugin.Dlna.Main.DlnaHost: Keuken - Playlist created
jellyfin  | [09:46:15] [DBG] [43] Jellyfin.Plugin.Dlna.Main.DlnaHost: Keuken - Playing 12 items
jellyfin  | [09:46:15] [DBG] [43] Jellyfin.Plugin.Dlna.Main.DlnaHost: Keuken - SetAvTransport Uri: http://192.168.2.43:8096/dlna/audio/24d92aa6-2629-4211-4593-4911a9f9f450/stream.mov?DeviceProfileId=13ef01b2db6343419b831bb7acce3738&DeviceId=bec5a406-f87c-4d29-a936-130a9a921415&MediaSourceId=24d92aa62629421145934911a9f9f450&Static=true&Tag=201f430d8123dadedeea6bb191a10e6d&dlnaheaders=true DlnaHeaders: DLNA.ORG_OP=01;DLNA.ORG_CI=0;DLNA.ORG_FLAGS=01D00000000000000000000000000000
jellyfin  | [09:46:15] [DBG] [43] Jellyfin.Api.Auth.CustomAuthenticationHandler: AuthenticationScheme: CustomAuthentication was not authenticated.
jellyfin  | [09:46:15] [ERR] [48] Jellyfin.Api.Middleware.ExceptionMiddleware: Error processing request. URL POST /Sessions/59221fd468a280888c4779c1622ce041/Playing.
jellyfin  | System.Net.Http.HttpRequestException: Response status code does not indicate success: 500 (Internal Server Error).
jellyfin  |    at System.Net.Http.HttpResponseMessage.EnsureSuccessStatusCode()
jellyfin  |    at Jellyfin.Plugin.Dlna.PlayTo.DlnaHttpClient.SendRequestAsync(HttpRequestMessage request, CancellationToken cancellationToken)
jellyfin  |    at Jellyfin.Plugin.Dlna.PlayTo.DlnaHttpClient.SendCommandAsync(String baseUrl, DeviceService service, String command, String postData, String header, CancellationToken cancellationToken)
jellyfin  |    at Jellyfin.Plugin.Dlna.PlayTo.Device.SetAvTransport(String url, String header, String metaData, CancellationToken cancellationToken)
jellyfin  |    at Jellyfin.Plugin.Dlna.PlayTo.PlayToController2.SetPlaylistIndex(Int32 index, CancellationToken cancellationToken)
jellyfin  |    at Jellyfin.Plugin.Dlna.PlayTo.PlayToController2.PlayItems(IEnumerable`1 items, CancellationToken cancellationToken)
jellyfin  |    at Emby.Server.Implementations.Session.SessionManager.SendMessageToSession[T](SessionInfo session, SessionMessageType name, T data, CancellationToken cancellationToken)
jellyfin  |    at Emby.Server.Implementations.Session.SessionManager.SendPlayCommand(String controllingSessionId, String sessionId, PlayRequest command, CancellationToken cancellationToken)