I can login to Outlook 365 in my web with MS Graph without user action. I'm using simple-oauth2 module and oauth2.ownerPassword.getToken method to generate tokens with username/password from my database.
I'd like embed Outlook.com in my web for each user (with their credentials).
Is there any way to do this?
Why would you do that?
If your application already lets the user login with Azure Ad account, you could use the on-behalf-of flow. Then your web application can request a token for another resource by sending the access token of the user for the current application.
If they aren’t logged in to Azure ad already you could have a look at the client credentials flow. Then your application will just get a token with access to all mailboxes.