I tried to reschedule an event but the guest did not receive the memo

Microsoft and Apple may create a shadow Outlook alias behind the scenes when you register for a Microsoft email (Hotmail/outlook.com) with a Gmail and for Apple, anytime the user choose to do so. So, when you try to email a guest via the email shown as the attendee, they may or may not receive the email. So, ensure that the guest has given you his actual email or that he has set to receive email routed from the alias. Please note these are calendar quirks based on the calendar used and MeetWithMe.ai is not the one introducing them.