There are a number of reasons your show may be rejected. If your podcast validates fine but receives an error after submission, the following issues may be occurring:
Podcast has already been submitted
If you've had a podcast on Apple Podcasts previously, it may be conflicting with your new Pinecast podcast. Apple will reject podcasts with names similar to shows that already exist on Apple Podcasts.
If the previous version of the show is a podcast that you're importing to Pinecast, you should consider adding a feed redirect on your previous host. This will migrate your subscribers to your new feed.
If you do not have access to your previous hosting provider (e.g., your subscription was canceled), you can still change the feed URL that Apple Podcasts uses. This will not migrate your existing subscribers, but all new subscribers through Apple Podcasts will use your new Pinecast feed.
Your podcast does not meet Apple's requirements
While it's possible that your podcast may have been rejected for content that is not--or is no longer--acceptable on Apple Podcasts, it's likely that this issue is caused by technical problems.
If you imported your show, Pinecast has not checked each of your assets for correctness. For example, Apple requires podcast cover art to meet a minimum size and use certain color settings. For imported podcasts, your previous host may not have respected these rules.
If you suspect this may be the case, please reach out to Pinecast support and we can help look into these issues.