What cron does DBManager use?

You can try to replace the WP Cron with real cron

https://support.hostgator.com/articles/specialized-help/technical/wordpress/how-to-replace-wordpress-cron-with-a-real-cron-job

What’s the URL we would need to activate the dbmanager backup and email via a cron job though?

Olly

There is no URL, it is handled by WordPress internal Cron API. It does not hit any URL directly in the plugin.

You can read about how it works https://code.tutsplus.com/articles/insights-into-wp-cron-an-introduction-to-scheduling-tasks-in-wordpress–wp-23119

Hmmm. Using that article I set up a cron job to call the WP cron every 5 mins rather than wait for users to hit the site (though we get 000’s per day).

Other WP cron based plugins are functioning but we don’t see any scheduled backups in dbmanager or get any of the backups via emails.

Manual ones work.

Is there a log files somewhere I can check?

Olly

Try saving the changes, it should generate a new cron and use https://www.ads-software.com/plugins/wp-crontrol/ to check the cron