Pro version

The schedule doesn’t run at defined time.
Follow this article  and replace WordPress cron with real cron.
Fri, 1 Dec, 2017 at 7:46 AM
I didn’t receive any emails for X hours.
Did you choose option “Since Last Run”?  You will get only new orders in this case, so you should create fake order to get the email.
Fri, 1 Dec, 2017 at 7:48 AM
Scheduled job skips some orders
if you  use "Since Last Run"   -   switch "Filter orders by"  to  "Modification Date" . See more detailed explanation below. ...
Wed, 18 Apr, 2018 at 1:10 AM
Enable logs for the jobs
1. Open a job (status change  or schduled) and mark checkbox  "Log results" 2. Wait till jobs run  3. Open the job again,  click link "View...
Fri, 1 Dec, 2017 at 8:22 AM
Debug scheduled jobs
1. Set  frequent schedule for the job ( for example, each minute)  2.  Enable   WP_DEBUG  3. Visit tab "Settings" and click on the url 4. Revie...
Fri, 1 Dec, 2017 at 8:37 AM