Event invites not going to recipient through the calendar

[Android Central Question]

I tried looking this up, but it seems the latest response was almost 3-years ago, so hoping someone can help!
Whenever I set an appointment in the calendar (I have a Samsung Gal. S6), and include an invitee, that person never receives the calendar invites. I have gone into the Exchange and made sure all boxes were checked.
It used to work just fine, and has now stopped working a few months ago.

 

[Rukbat]

Not many email apps work correctly with Exchange Server (not even Outlook) - there are just too many different ways to set Exchange up. That goes double for calendar apps.