When sending a Broadcast only some emails are sending

With the release of Groundhogg 3.0, Broadcasts are scheduled in the background using WordPress Cron. This is different than the gh-cron.php . If WordPress cron is not running, then the broadcasts can't be scheduled.

We would suggest setting up another external cron job that points to /wp-cron.php at regular intervals. Set to every 5-15 mins.