ActiveSync: Outlook 2019: synch slow, or non-existent

If you are using ActiveSync and experiencing issues with slow calendar synchronization between Outlook and phones and other devices:
Try changing Outlook's send/receive frequency from every 2 minutes, to every 5 minutes(or longer) to let the server fihish the sync.

Directions form Outlook: https://support.microsoft.com/en-ie/office/change-send-receive-group-settings-7184f59d-c194-44d7-973a-7af568a918d0