I set up a podcast (corona-wg.de) and got listed on Apple Podcasts. After some episodes the feed stoped to continue on Apple Podcasts - only! The feed itself work properly.
The podcastconnect site states the following issue:
Incompatible SSL certificate. PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
After I asked the Apple support the replied:
Upon further review, it appears the issue being experienced is related to the current SSL certificate being used in your RSS feed URL.
It looks like you are using Let’s Encrypt, and this is not a supported Certificate Authority. You will need to use a different Certificate Authority in order to stream your episodes on Apple Podcasts.
I’m suprised by this anwser as I by myself use the same setup for another podcast with let’s encrypt and everything works just fine - even on ApplePodcast.
Would be great if anyone could help. (Especially as I’m completely lost with this issue even on the german sendegate community).