To login with the password generated by Microsoft Office 365 for Regain OST to Office 365 Migrator software, perform the steps as discussed below:
Note: The above-mentioned steps are for Basic Authentication.
While trying login using Basic Authentication, if you are facing an error “Failed (401 unauthorized error)”, then you need to try login Multi-Factor Authentication as this is a new security feature by Microsoft Azure.
To understand how to perform Azure App Registration and how to generate Azure App Client ID and Azure App Tenant ID, refer Appendix A - Azure App Registration & Generating Azure App Client ID & Tenant ID.
To understand how to enable Multi Factor Authentication (MFA) for Office 365 account for Admin, refer Appendix B - Enabling MFA for Office 365 Account - Admin.
To understand how to enable Multi Factor Authentication (MFA) for Office 365 account for a user, refer Appendix C - Enabling MFA for Office 365 Account - User.
To understand how to generate App password for Office 365 account, refer Appendix D - Creating App Password for Office 365 Account.