We are really struggling to allow our users to log in and authenticate with Google (OAuth 2.0). We need to also get permissions to send email on behalf of our users from within the app (https://developers.google.com/gmail/api/v1/reference/users/messages/send).
For now we would like to get this up and running, then eventually look to have the same sign in (& send emails on behalf of) Exchange accounts too.
Would love to speak to anyone who can help us out.
Tim & Alex