Proper cron task must be configured for publising scheduled posts. Otherwise scheduled posts will not be published. Also there might be some modules which uses the same cron task.
Cron task should run once per minute. In some servers, minimum interval for running cron tasks is 15 minutes. If you set interval to 15 minutes, all of your scheduled posts still will publish. But publish time might delay up approximately 15 minutes.
Scheduled posts are being published by opening
/cron page in your app.
So if you've installed the app to
www.example.com then cron URL will be
Complete cron task should be similar to:
* * * * * wget --quiet -O /dev/null http://www.yourwebsite.com/cron
If you your cron task didn't work with previous command, then you can try with following command:
* * * * * wget -- spider -O - http://yourwebsite.com/cron >/dev/null 2>&1
Don't forget to replace
http://yourwebsite.com/ with the actual URL of your app.
If your server doesn't support cron task, then you'll not be able to schedule posts successfully. Then you should either change your server or use external cron task services. There is not any other workaround, please don't ask.
Check easycron.com if you're looking for external cron task service.