Hi Jenny,
You can control which events generate emails from the Event Management page on the SZ GUI
To enable or disable email option per event, highlight the event and hit enable or disable pull down menu
AP disconnection is preceded by AP heartbeat errors (314) then AP disconnect (303) and then reconnect (312). You may also be receiving a change of control plane event if you have multiple nodes cluster (311). You can determine which of these messages are important enough to notify you by email.
DB persistence determines if the event is stored in the SZ.
I hope this information is helpful
Thanks
Albert