Adding Organizations with Modern Authentication and Legacy Protocols
When you add an organization using the modern authentication method with legacy protocols allowed, you use both Veeam Backup account and Azure AD application for authentication. Veeam Backup for Microsoft Office 365 uses Veeam Backup account and an application to establish a connection to your Office 365 organizations with disabled security defaults and maintain data transfer during backup and restore sessions.
To add a new Microsoft Office 365 organization, check prerequisites and do the following: