Let’s dig right into this so we can get you back to easy scheduling! 

For some context, with Calendly, there are two types of notifications: Email Confirmations & Calendar invitations.

1. With Email Confirmations, Calendly sends the invitee an email notification from notifications@calendly.com and has a reply-to address that's associated with your Calendly login email. You can modify this on Account Settings page.
2. With Calendar Invitations, your connected calendar sends the invitee a notification of the booked meeting which has a reply-to address that's associated with your Add to calendar email on your Calendar Connection page.

Note: Calendar invitations are not compatible with iCloud Calendar or the Outlook Plugin (for Windows users). Users with either of these calendar connections set up as their "add-to calendar" on their Calendar Connection page will be defaulted to Email Confirmations. 

In many cases, resolving this issue is as simple as heading into your event type settings (this setting is event specific, so you’ll need to do this for each event you wish to send Calendar Invitations from)  click “Notifications and Cancellation Policy”  click “Switch to Calendar Invitations” underneath “Email Confirmations”  click “Save and Close.” As long as you have a compatible calendar, as noted above, it’s as easy as pie!  

You can learn more about invitee booking notifications in this Help Center article!