Activating Auto Publish Posts Module
In the Admin Optimizer page, click to enable the Auto Publish Posts with Missed Schedule module. Press Save Changes to save the changes.
The module will now check the site every 15 minutes and auto-publish posts that have missed their schedules.
Note: If you are using WordPress cron, the schedule will only be triggered when someone visits your site. For best result, it is best to switch to a proper cron job in your web host to ensure tasks are run timely.