Automatic updates can be interrupted by a number of things.
We encourage you to read a little bit of the background of WordPress automatic updates to get a better understanding of it and help you troubleshoot it.
If Shield is indicating that Automatic Updates is turned on (which it is by-default for WordPress minor core upgrades), and it doesn't seem to be happening, these are just some of the reasons why:
- Your WordPress cron isn't working. Have a look on your Shield Insights Dashboard under "Recent Events" and look for the time of the last simple cron. If this hasn't run recently, your crons probably aren't working.
- Another plugin/theme is interfering with Automatic Updates. Check your plugins and themes to see whether they are also modifying this behaviour. Disable them for a day or so to test, if you have to.
- You have some WordPress PHP "defines" set that are completely disabling automatic updates. These defines are usually set in your wp-config.php file, or your themes functions.php. You can learn more about which defines affect what, here: https://codex.wordpress.org/Configuring_Automatic_Background_Updates
These are the 3 major ones to look out for.
Shield can only indicate to WordPress which things it should automatically update. But if something else is doing the same thing, or certain actions are disabled, or your WP Cron is broken, there is nothing that Shield can do about that.