You may import your private RSS into "Your Library" for your own use by copy and paste the RSS feed in the search box in Castbox Android or iOS app.
Such private RSS will stay as private data to the user, and can not be accessed by any unauthorized parties.
If the RSS feed requires authentication, you will need to embed your username and password in the RSS URL by following the patter below:
https://username:password@the_rss_feed_url/ where 'the_rss_feed_url' is your podcast RSS feed url WITHOUT the 'http://' prefix.
After that, you could simply search the supplemented URL in the search bar and import it on Castbox Android or iOS App.
If you still fail to import, would you mind sending us the URL with your username and password? You could reach us at
contact@castbox.fm. Please do not worry, we would only use them for a test.