@vondelphia, I did find a resolution. Not 100% on this, but it is working on my side now. In Azure Dashboard, I enabled the Microsoft Graph API to allow the mail app to send email, and also readwrite email. Initially this did not work; however, I believe this is due to the fact that I enabled the API after I had generated the access token. I went back in and regenerated the Access token and the authentication now works perfectly.
