Been working my butt off to get this working. Now upgraded to DNNv4.8.2 and things "seem fixed".

I get no error messages at all from the scheduled tasks and they seem to be running.  I am not getting any forum notifications though... and I think I've checked every possible related setting for this. The schedule history for the forum emails says it succeeded but also says "Email Queue Task Completed: No Emails Returned To Send". Why would that be?

Is there a way to actually test the scheduled tasks are doing something?

The key task I think is:

Full Class Name and Assembly This is the full class name followed by the assembly name. Example: "DotNetNuke.Entities.Users.PurgeUsersOnline, DOTNETNUKE"
Schedule Enabled Check to enable the schedule.	Yes
Time Lapse: Example: "5" and select "Minutes" to run task every 5 minutes. Leave blank to disable timer for this task.	Seconds Minutes Hours Days
Retry Frequency Example: "5" and select "Minutes" to retry the task every 5 minutes after a failure. Leave blank to disable retry-timer for this task.	Seconds Minutes Hours Days
Retain Schedule History: Example: Select "10" to keep the ten most recent schedule history rows.	None 1 5 10 25 50 100 250 500 All
Run on Event: Example: Select "Application Start" to run this event when the web app starts. Please note, events run on APPLICATION_END may not run reliably on some hosts.	None APPLICATION_START
Catch Up Enabled: If checked, if the webserver is ever out of service, when the webserver is back in service this event will run once for each frequency that was missed during the downtime.	Yes
Object Dependencies: Enter the tables or other objects that this event is dependent on. Example: "SiteLog,Users,UsersOnline"
Run on Servers: Enter a comma delimited list of servers that this task should run on.

Is it correct for this one - no Object Dependencies?

From testing, when a thread is post , the table "Forum_EmailQueue_Tasks" is showing SendComplete is True for each item, even before the schedule task is run. The EmailPriority and SentEmailCount for all items shows as 0. Does this seem right?

Also... what is the difference between the scheduler modes (request or timer)? Hoping someone can explain it quickly in plain English (mine is currently set at timer).

Thanks