Usage This setting is used to determine whether a user is an Office 365 / Azure AD user in your organizational directory or not e.g. when a user attempts to sign into your website manually, change his or her email address or password or when the plugin tries to retrieve an Office 365 profile image instead of the WordPress avatar (depending on the installed plugin edition).
To see your custom domains you can navigate to the Azure Portal Azure Active Directory Custom domain names.
To support enterprises that have mapped multiple domains to their Office 365 tenant, you can add more than one custom domain.
Only fill out if you added a custom domain e.g. mycompany.com to your Office 365 account, otherwise leave empty. Do not add the cloud-only yourcompany.onmicrosoft.com domain here.
Important After you entered a domain name in the input box you must click “+” to add it. This is also true when you are entering just one domain.
Default value empty.