I received this diagnosis from my web host support, websavers.org, after I verified the host server settings had not been changed by them:
It appears the feed URL is providing a 404 error first, then proceeding to the RSS feed. I thought at first this might be because nginx isn’t following the WordPress’ rewrite rules for the RSS feed, but I flipped off static file processing with nginx in order to have everything processed by apache and ran into the very same issue.
My guess at this point is that the RSS feed plugin is attempting to override requests for “http://www.mountainviewbible.com/feed/podcast” via WordPress hooks that are supposed to be higher priority than the WordPress 404 fallback, but for some reason as of the latest update the priority is now wrong, causing the 404 to come before the RSS feed.
Does someone have an idea for a fix or a workaround?
This is still not resolved even after the latest update to the sermon manager plugin.
I finally figured out the problem that caused the 404 error to occur on our podcast feed. Our site did not have any regular “blog” posts published because we only publish “sermons” through the sermon manager plugin. Apparently, if you do not have any regular blog posts on your WordPress site, your other feeds will not appear correctly because there is some extra code or spaces at the top of the secondary feeds that basically invalidates the feed. I added a test “blog” post and immediately this resolved the issue. After deleting the post, the feed failed the validation test again and returned a 404 error. My guess is that this is an issue within WordPress and not the Sermon Manager plugin.
Solution: Publish at least one regular blog post on your WordPress site.
