Apple's Photos app has stopped downloading photos from iCloud (though I can confirm that they are present in iCloud.com and all my other devices). Only recent photos seem to be missing. I've waited a day, an still nothing. I've rebooted, turned Photos off and on in Account settings, force quit Photos, etc. I've even repaired the photo library. There is no indication that the Photos app is syncing.
How do I get Apple's Photos app to download recent photos from iCloud?