Zoho Calendar and Microsoft Calendar Interoperability

Zoho Calendar Interoperability allows Zoho Calendar users to interact with users on Microsoft (Exchange on-premises/ Exchange online/ M365/ Office 365) to view each other's availability. Once the interoperability is setup successfully, the users on both the platforms check each other's availability seamlessly while scheduling an event.

System Requirements

The following system requirements are mandatory to perform Interoperability between calendars in Microsoft and Zoho:

Microsoft Exchange requirements

• Microsoft Exchange 2013 or 2016 (on-premises) or Microsoft Exchange Online (Microsoft 365 / Office 365)
• Inbound and outbound internet connectivity for Exchange Web Services (EWS)
• An SSL certificate for the Exchange server. (The certificate should be issued by a trusted public root certificate authority.)
• A Microsoft Exchange role account for Zoho Calendar to access and check the availability of Microsoft users.

Zoho requirements

A Zoho role account for Microsoft to access and check the availability of Zoho Calendar users.

Authentication

• Microsoft announced that it will begin disabling Basic authentication for EWS from Oct 1, 2022, and instead provide support for OAuth 2.0. Refer to the Deprecation of Basic authentication in Exchange Online for more details.
• Zoho Calendar Interoperability supports Basic authentication for on-premises Microsoft Exchange and OAuth 2.0 for Microsoft Exchange Online (Microsoft 365 / Office 365).

Add an email alias using a sub-domain

If you use the same email domain address (zylker.com) in both Zoho and Microsoft, you need to add an alias using a sub-domain to the users in Zoho. There will be a conflict if the domain name used on Microsoft for Zoho users is the same as the domain used by Microsoft users since Microsoft directs the free/busy status request based on the domain name.

It is recommended to use a separate sub-domain to provide the email alias to the users in Zoho. It can be zoho.zylker.com if the domain name is zylker.com. When you configure the settings for Microsoft, you need to provide the email alias based on the sub-domain in the availability address space for Zoho Calendar in your Microsoft server instead of the users' primary email address.

To use an email alias using a sub-domain follow the steps given below:

1. Configure the sub-domain that you are going to use for the email alias of users. The domain address used in Zoho should not be the same as the one used by Microsoft users.
   • Refer here to configure the domain.
   • Refer here to create an email alias for users.
2. After the domain addition, you need to configure MX records pointing to Zoho for the sub-domain added in the DNS provider settings.
3. You need to use the email alias in the following situations before proceeding to configure the setup for Zoho Calendar users to look up the availability of Microsoft users.

   • When setting up mail contacts for Zoho users on Microsoft: The primary email address of the Zoho contact in Microsoft (usually given in the bold text) should be the email alias based on the subdomain (paula@zoho.zylker.com) and the email address of the contact based on the primary domain (paula@zylker.com) should be added as an alternative email address in Microsoft. Refer here, for more details about setting up Zoho users.

     Note

     You can add the original Microsoft email address of the contact as an extra SMTP address for the contact.

   • When adding a new availability space in Microsoft: You should use the email alias using the sub-domain when prompted to add contacts in the configuration tool. Learn more.
4. You can send a test email from your Microsoft server to a Zoho user using both their primary domain email address (paula@zylker.com) and the email alias using the sub-domain address (paula@zoho.zylker.com).