Calendar E-Mail Extension for Office 365 Configuration

Applies to: Calendar E-Mail Extension for Office 365/SharePoint online
Other versions: View the version for SharePoint on premise (SP2010, SP2013, SP2016, SP2019)

This guide assumes that you have already added the Calendar E-Mail Extension Add-In to your SharePoint Online site.

In this article:

How to configure

There are two different ways to configure the Calendar E-Mail Extension Add-In:

1. “One-click” configuration

The “one-click” configuration is recommended when using the add-in for the first time. This setting is the quickest and easiest way to set up the Calendar E-Mail Extension Add-In. Using the options e-mails are sent via our mail service, which also receives status replies from attendees. Unfortunately this configuration does not have access to Exchange and you will therefore not be able to check the availability of rooms and equipment or attendees in Exchange. If you require these features you must use the second configuration option.

On the add-in’s start page click on the Configure link for the calendar you want to configure, or in the calendar list’s ribbon click on the CALENDAR tab and then on E-mail Settings in the Settings section.


E-mail settings

From the three options for Calendar E-Mail Extension, select the second one: Send invitations.

Send invitations

Once you have clicked on Save, the calendar list is ready to send invites and receive status replies from attendees. You can, of course, continue configuring other details such as the e-mail alias, display name, contact lists for guests and so on.

2. “Integrated with Exchange Online” configuration

This configuration option is more advanced than the first option, however, it allows you to check the availability of rooms and equipment in Exchange, as well as the availability of attendees. Additionally you can book resources and send e-mails via Exchange. In order to use this setting, you need an Exchange Online user configured in Office 365.

How to: Configure E-Mail Settings using a user account

You now have access to all features of the Calendar E-Mail Extension Add-In and can send invites, receive status replies and book rooms and equipment using Exchange Online.

Final steps

To complete the configuration of the Calendar E-Mail Extension Add-In, you also have the option of improving the user experience by adding more functionality to the ‘Check Resource Availability’ action in the new and edit forms. By adding a script to these forms you can check the availability of attendees and resources with a single click as they are entered. Follow the instructions in this blog post to add this great feature to your calendar events and check attendee and resource availability in calendar events on SharePoint Online Office 365.

All other configuration options should be self-explanatory or the short explanation found on the configuration page should be sufficient. We hope you like our new Office 365 / SharePoint Online add-in. We will of course keep you updated with information and tips via our blog, which can be found here. If you have any problems or questions, please send an e-mail to