Microsoft Graph, Outlook, OAuth2, Resources, Audiences…
Here I’m just relaying bits of knowledge from a great Chilkat customer…
“I learned meanwhile that Microsoft doesn’t like mixing “resources”, so if you request something from “Graph” resource and “Outlook” resource, they are incompatible resources, so you have to request different tokens for both, or request resource for only Graph and then refresh token only for “Outlook” resources – it is described here:
The “User.Read” line is crucial for reading user data (“me”) (after adding it – it works), but then it doesn’t work when using token on IMAP/POP/SMTP (it would probably work if using Graph API, but IMAP/POP/SMTP are “Outlook” API. And you can’t get a same token as then it issues an error if you include https://outlook.office.com/ before as then again it mixing “resources”. Whatever. It is a complete mess.”