We have found out that Pocket Cast uses a very odd way of validating password protected RSS feeds. You have to modify the Feed’s URL before submitting it to their system.
The format is
https://username:password@[restof feed link].
For example, if you wanted to add D&D is for Nerds Vol 4 Burried Beneath would be:
Note: As your username is your email it already has an ‘@’ in it. Your formatting will be slightly different as you need to replace the @ in your username with %40 This means it would look like the below: