We have Magento CE 184.108.40.206 where AOE Scheduler is configured for cron, and Magento cron is set to run on system after every 30 minutes as follows and shows no issues in /var/log/cron
*/30 * * * * /usr/bin/php /home/www/vhosts/example.com/httpdocs/cron.php
But, for some reason on back-end we always see error "No heartbeat task found. Check if cron is configured correctly." like follows and all status grayed and are always set to 'PENDING'
Following are the settings for System > Schedular > Job Configuration
And following are the settings for System > Cron Configuration
If we run the cron manually via command line or via browser than "No heartbeat task found..." issue goes for some minutes but again comes in, also if settings Magento cron to run every 5 minutes it goes away! but that overlaps other running tasks so we have to run it every 30 minutes at least.
What could be the issue here with 30 minutes interval which always shows "No heartbeat task found..." and all tasks pending to grayed with PENDING status?