Sometimes the audio files uploaded to Telegram's servers, and then retrieved with their File ID, are returned as Unknown.file and thus are not playable inside the app. The file can be downloaded, and is a correct mp3 file, as it becomes playable when the ".mp3" extension is added to the filename.
What exactly causes some audio files to lose that identity on Telegram's servers is unknown.
Sometimes the audio files uploaded to Telegram's servers, and then retrieved with their File ID, are returned as Unknown.file and thus are not playable inside the app. The file can be downloaded, and is a correct mp3 file, as it becomes playable when the ".mp3" extension is added to the filename.
What exactly causes some audio files to lose that identity on Telegram's servers is unknown.