Relevant products: Signature Manager Outlook Edition
Scenario
You are using Signature Manager Outlook Edition where the user mailboxes are hosted on Exchange Online/Microsoft 365. Now, you want to use the multi-factor authentication (MFA), on the account used by Signature Manager Outlook Edition, to update the user's signatures.
Resolution
Signature Manager Outlook Edition only supports basic authentication. In order to use MFA on the account configured to update the OWA signatures, you need to generate an app password for the Microsoft 365 account. Then, you need to enter the app password in the Update OWA from Server - Configuration window:
Note: For more information, see this article from Microsoft on how to Create an app password for Microsoft 365.