WP-cron not running.

wp-cron depends on site visits to get triggered, and it’s a fairly common problem for low-traffic sites to miss scheduled posts & other scheduled tasks.

Try this plugin: https://www.ads-software.com/plugins/wp-cron-control/

This is not a low traffic site, there’s always at least 1 active visitor. I also tried that plug-in you mentioned, I said that in my post.

Sorry. I missed that you had tried the plugin in your original post.

You could try disabling wp-cron, and going with an external cron. If that’s a little complicated for you, you could try this plugin: https://www.ads-software.com/plugins/easycron/

You would need to sign up for the free level of easy cron to make this work.

I did that too.