Podcasts are Not Downloading

Hey,

my podcast episodes are not directly downloading onto my iphone's podcast app.

Others are having the same problem. Some episodes show up fine, but others are not.

They are showing up when you manually search for them in itunes, but dont seem to be featuring in the podcast feed on the app itself.

Any ideas how to fix this so they will all be featured and downloaded automatically?

Thanks

Cormac