I have the EXACT same issue with my own account. Interested to see if this goes anywhere...

This seems to have still not be resolved. Has there been any progress at all on this issue?

Worth adding too that just like @benzgrant I get the same error using the official web player, and it also occurs when loading the list of library artists, but not songs or playlists. Requesting the library artists returns { "errors": [ { "id": "OVBAPGJPXEC6DUKGRJSEHIFG3Q", "title": "Upstream Service Error", "detail": "Error fetching library content", "status": "500", "code": "50001" } ] }