In Daylite, when you add a Person to an Appointment's Invitee's section, once you save the Appointment Daylite should prompt you to send the invite (see screenshot below):
To fix this issue, follow the steps below:
- go to System Preferences
- click Security & Privacy
- click the Privacy tab
- unlock the padlock at the bottom
- on the left hand side, scroll down and click Automation
- on the right hand side, scroll down and under Daylite check ON Mail (see screenshot below)
- close System Preferences