See https://learn.microsoft.com/en-us/exchange/client-developer/legacy-protocols/how-to-authenticate-an-imap-pop-smtp-application-by-using-oauth#use-client-credentials-grant-flow In my opinion, this is still too complicated. An “easy button” is needed.
This post documents how to implement Modern Authentication (OAuth2) for Office365 for the IMAP, POP3, and SMTP protocols. The very first thing you’ll need to do is to create an “App Registration” in Azure Active Directory. See this Chilkat blog post for Instructions for Setting Up an App Registration in Azure for Modern Authentication for IMAP, SMTP, and POP3. It’s […]