Adding Organizations with Modern Authentication
[Information in this section is applicable to Veeam Backup for Microsoft Office 365 version 4c only.]
When you add an organization using the modern authentication method, you are required to provide Azure AD application settings. Veeam Backup for Microsoft Office 365 uses such an application to establish a connection to your Office 365 organizations with enabled security defaults and maintain data transfer during backup and restore sessions.
With modern authentication, you cannot use a user account; only communications via an AD application is possible.
To add a new Microsoft Office 365 organization, do the following: