Invalid RSS 2.0 specification?

I submitted my feed to, and I received an email back from them saying that the feed was invalid.

Here is what they sent:


Thank you for contacting us regarding this issue. We were unable to add the podcast feed that you've submitted to TuneIn. This is likely due to your feed missing audio files or the feed does not conform to the RSS 2.0 specifications. For more information about this standard, please visit:

Let me know if you have any other questions.

TuneIn Broadcaster Support 

Here is the URL of my feed:

What am I doing wrong?

Feed looks okay to me. I would press TuneIn explaining exactly what they think they complain about. I cam‘t see anything wrong.

Well, I don’t know what changed, but now my podcast appears in their directory, even though they never got back to me.