I have been using schedule posts for over a year with no problems. About two weeks ago, they stopped working. Sometimes a schedule post will show "missed schedule" and sometimes it claims to be published.
I checked the timezone and that is set correctly.
I saw something about the first visitor the blog triggering the post. My posts go out to LinkedIn, Twitter, and FB. When scheduled posts was working correctly, I saw my posts go out over those platforms on schedule.
My ISP claims to have made no changes to cron settings.
My blog is http://blog.7stepsahead.com.