A scheduled newsletter is sent when WordPress publishes it, and that depends on WordPress cron. If cron doesn’t run on time, the newsletter can be late. Since Newsletter Glue 4.3, a check runs every minute. It finds scheduled newsletters that are overdue, then publishes and sends them.
Newsletters that were stuck when you updated
When you update to 4.3, a newsletter that is already more than 5 minutes past its send time isn’t sent automatically. Newsletter Glue holds it, so old news doesn’t land in inboxes by surprise.
Users who can publish newsletters see a notice in the WordPress admin: 1 scheduled newsletter missed its send time and was not sent. It lists when each newsletter was scheduled and how late it is. Choose what to do:
- Send now: send it to your subscribers now.
- Publish without sending: publish the post on your site, with no email.
- Unschedule: move it back to draft and cancel the newsletter.
If the post is already published, the choices are Send now and Don't send. With more than one held newsletter, you can use Send all now, Publish all without sending or Unschedule all. The same choices appear in the Newsletter Glue box when you edit the newsletter.
Newsletters sent late
Any other scheduled newsletter that’s overdue is sent as soon as the one-minute check runs. When that happens, you’ll see a notice: “A scheduled newsletter was sent … late because WordPress cron didn’t run on time.” The newsletter’s status log notes the delay too.
Stop it from happening
Set up a server cron that runs every minute, so WordPress cron runs on time even when your site is quiet. The notice’s Set up cron link helps, and My automations are not firing has step-by-step instructions.
Sites with an object cache
Before 4.3, sites with a persistent object cache, such as Redis or LiteSpeed, could leave a newsletter stuck in “Scheduled”. The one-minute check reads straight from the database, so a stale cache can’t hide a newsletter from it. 4.3 also stops scheduled campaigns from sending twice on sites with more than one cron trigger.