Why is my podcast validating correctly but getting rejected by iTunes? I have a podcast that passes all validation tests I can find, yet iTunes won't accept it. I'm hoping someone here can tell me what's wrong with it. 

The feed is http://www.loatoday.net/feed/mp3/

It validates correctly at validator.w3.org/feed

It validates correctly at castfeedvalidator.com

It validates correctly at www.feedvalidator.org

It even passes validation at podcastsconnect.apple.com/#/new-feed

The only possible problem I can find is a warning message that states, "line 1, column 38: Use of unknown namespace: http://podlove.org/simple-chapters"

I've checked with the developer of the WordPress plugin (Podlove Podcast Publisher), but they claim that this shouldn't be a problem and that all of the other podcasts using their plugin (they have more than 2000 installs) work just fine in iTunes.

I've asked for help at discussions.apple.com and the resident iTunes help expert (Roger Wilmut1) at that site says he can't find anything wrong with it either.

I've tried writing to PodcastSupport@apple.com for their assistance on two different occasions over the past 8 days, but so far I have received no reply from there, either.

The error email I receive doesn't really help either. It says: "An error was encountered while trying to add your feed."

That's all it says about the error. Then it gives me links to standard podcast resources.

I'm at a loss what to do next. Can anyone here tell me why Apple keeps rejecting my podcast feed submission?

ADDITIONAL EDIT: Just for the heck of it, I tried commenting out the namespace that the validators didn't like. It validated again, this time without incident, in all four places, but submitting the podcast resulted in the same, non-descript error email.

Any help anyone can give would be greatly appreciated.
Well, it looks like the problem may have been related to http vs https.

I found this interesting note on Apple's "Podcast best practices" page at https://help.apple.com/itc/podcasts_connect/#/itc2b3780e76

"Pick a reliable podcast host and be sure to host podcast episodes, artwork, and XML on an HTTPS-authenticated server. Podcast providers are reliant on the up-time, security, and speed of the podcast host distributing their RSS feed, podcast artwork, and episode files. For more information, see Podcast Partner Search."

So I added an SSL cert, cleared the cache, and resubmitted. This time, I got an email back saying, "Your podcast feed, [ https://www.loatoday.net/feed/mp3/ ] was successfully added and is now under review."

This is particularly weird because Roger Wilmut1 over at discussions.apple.com told me that Apple used to refuse https feeds. So apparently this is a change they instituted sometime in the past year or two. Maybe it is an outgrowth of the Apple vs FBI controversy over the terrorist's iPhone earlier this year? Who knows?

All I know is that by changing http to https I was able to get Apple to accept my submission for review.