Hi there,
I have checked with the RSS feed and found the exact reason for the problem.
The problem: The host of your audio file adds access tokens to the mp3 files url as query strings. If we try to access these mp3 files without those access tokens, error message will be thrown.
Unlike other podcast apps, generally we have to remove query strings from the mp3 file to work with default WordPress functionality. Therefore, those access tokens are also removed and mp3 file does not play.
The solution: I have made necessary changes in the plugin to handle such edge cases. I have included zip file of the plugin at the bottom of this message. It should work perfectly with your case. However, I will test it further with other podcasts and officially release an update to the plugin.
Meanwhile, you just delete podcast player plugin from your WordPress installation and re-install from the zip file attached.
Link to download zip file – https://send.firefox.com/download/f76d9d93f7c6ab88/#gSaCYYJVz2AiMKTa5T9Bhg
Inform if you need more help on this OR any other help is required.
Thanks,