Thank you for replying. I’ve had my WordPress blog hosted by Yahoo for years with no problem until the last month or two. But I’ll contact them and see if the problem is at their end. If not, I’ll try the manual updates as you suggest.
Most of the problems are in the blog management (updating plugins, themes, etc). But many of the pages on the site (though not all) are also not loading. This should be an example: http://policegazette.us/blog/2017/07/09/police-gazette-publishes-new-plays-by-famed-off-broadway-playwright-leonard-melfi/
Thanks. I ended up having to call Yahoo (not least because I forgot my phpMyAdmin password) and they fixed it.