Cannot create Track Radio. Error: "No external mapping for item"

[hairyfry]

Server Version#: 1.24.3.5033
PlexAmpVersion#: 3.7.1

After updating my server to version 1.24.3.5033, whenever I try to play a song radio on Plexamp it says “Couldn’t start playback”. I can no longer create radios from songs. Library radio still works as does mood radio. Both the desktop and android versions of Plexamp give me the same error and I’m not sure what to do as it worked just fine a day or two ago.

Current plex server is running in a Windows VM and has worked just fine for over a year. Sonic analysis has been great and I’ve loved listening to the radios it generates.

When I check the server logs it says:

Sep 26, 2021 22:28:50.713 [4560] Debug — PlayQueue: 0 generated IDs compressed down to a 20 byte blob.
Sep 26, 2021 22:28:50.715 [4560] Debug — [Track Radio] Starting with seed track 6105 (Home / Pyxis).
Sep 26, 2021 22:28:50.716 [4560] Warning — [Track Radio/Music] No external mapping for item 6105 of type 10.
Sep 26, 2021 22:28:50.717 [4560] Debug — [Track Radio] Got 0 tracks.
Sep 26, 2021 22:28:50.717 [4560] Debug — [Track Radio] Augmented similar artists with 0 sonically similar.
Sep 26, 2021 22:28:50.717 [4560] Debug — [Track Radio] 1 similar artists, 1 second order artists.
Sep 26, 2021 22:28:50.717 [4560] Debug — Radio: Stepped the radio generator for artist 'Pyxis' in 0 ms.
Sep 26, 2021 22:28:50.717 [4560] Debug — Radio: We're out of tracks, time to revisit the existing tree.
Sep 26, 2021 22:28:50.717 [4560] Debug — Radio: We're out of tracks, time to revisit the existing tree.
Sep 26, 2021 22:28:50.718 [4560] Debug — Radio: We're out of tracks, time to revisit the existing tree.
Sep 26, 2021 22:28:50.718 [4560] Debug — Radio: We're out of tracks, time to revisit the existing tree.
Sep 26, 2021 22:28:50.718 [4560] Debug — Radio: We're out of tracks, time to revisit the existing tree.
Sep 26, 2021 22:28:50.718 [4560] Debug — PlayQueue: Start index: 0 End index: -1 Count: 0
Sep 26, 2021 22:28:50.718 [4560] Debug — PlayQueue: 0 generated IDs compressed down to a 20 byte blob.

I’ve attached the zipped log files if someone finds them more useful.
Plex Media Server Logs_2021-09-26_22-44-36.zip (6.2 MB)

Edit: Here is also a screenshot of the error in Plexamp as it appears on my side.

[Weirdomusic]

I can confirm I have the same issue (Windows 10 / iOS / latest version of server).

[hairyfry]

Update: After trying a few things I got it working again by turning off Sonic Analysis in my music library settings, adding a few more songs to my library and then turning analysis back on. After picking up the new songs the Dashboard displayed “Rebuilding artist index” for a while and now I can once again use Track Radio.

Not sure what caused it to break in the first place but it works again.

Update again: It happened again and I solved it using the above method. I’m also observing server crashes when Sonic Analysis is running. If the server crashes during analysis it (maybe?) corrupts the analysis or artist index or something. If there were a way to manually trigger the rebuild of the artist index I could fix it without having to add more music to analyze to then trigger the index rebuild. Oh well, I guess it’s working now ¯\(ツ)/¯