1. Create a new appointment > include participants: two participants that belong to your company (internal) and one participant that does not belong to your company (external).

2. Make sure to activate the "E-mail invitation" for all of the participants.

3. Send the appointment invitation.

Observed that: when the invitation is sent out - Web tools start the process of sending it - however when checking the sent items folder in the e-mail client (in this scenario Outlook) - it does not show any invitation being sent out.

Additionally, when the appointment is canceled - the e-mail of the cancellation is sent out to the participants and occurs in the sent items folder. 

Expected that: the appointment invitation would be sent out to all of the participants.