I am trying to set up a blog for someone to post on, and the posts will feed to another page via RSS. But I can't get the RSS feed from the core Blog module to work in either, News Feeds, FeedReader Lite or XML (although I am very confused by the last).  Any ideas?

The RSS feeds require that the SearchEngineScheduler scheduled task be running. You can see if this is the case from the Hosts, Schedule page.

Thank you so much for a response! The scheduler is running, but I recently upgraded to 4.9.1 and I think the scheduler is awry.

Have you checked to if the scheduled task runs successfully?

Yes, it says it is scheduled for every 30 minutes but the same scheduling issue has been driving lots of other problems in other modules.

Are you getting errors related to the scheduler?