iTunes rejecting my podcast

Most likely your are placing your media files directly into the posts. You need to use the podcasting section on the edit page to add your media:

https://docs.podcastingplugin.com/help/setup/adding-a-media-file/

This allows the media control the plugin needs.

The podcasting plugin handles including the media files. It needs to handle the media file so it know how to handle them. Plus it adds some additional features like allowing the user to open the player in a few window.

This means the audio or video files place directly in your post will not be include the feed sent to iTunes. I understand that this is a bit confusing, but it plugin needs to have more information about the media files included in the feed.