Subject: connecting to Outlook 365 (IMAP and SMTP) using OAUTH2 , AUTHENTICATE failed (NO)
Date: 2022-09-29 14:13:27
From: ERIC MEHN
Source: connecting-outlook-365-imap-smtp-using-oauth2-authenticate-failed-no
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Hello all,

I'm trying to connect to outlook 365 through my console application(C#) using OAUTH2 but I keep getting **AUTHENTICATE failed (NO)** when authenticating the connection. I have tried the same acquired token with another library and I was able to connect, Authenticate and read my emails. 
I also disabled the Multi factor authentication in Azure.
Please advise.  


            var clientApp = ConfidentialClientApplicationBuilder
                .Create("ClientID")
                .WithTenantId("TenantID")
                .WithClientSecret("ClientSecret")
                .Build();

            var authenticationResult = await clientApp
                    .AcquireTokenForClient(new[] { "https://outlook.office365.com/.default"})
                    .ExecuteAsync();

            var accessToken = authenticationResult.AccessToken;


            string rawToken = string.Format("user={0}{1}auth=Bearer {2}{1}{1}", email, '\x1', accessToken);
            string rawXOAUTH2Token= Convert.ToBase64String(Encoding.ASCII.GetBytes(rawToken));

            ComponentPro.Net.Mail.Imap imap = new ComponentPro.Net.Mail.Imap();
            await imap.ConnectAsync("outlook.office365.com", 993, SslSecurityMode.Implicit);
            await imap.AuthenticateAsync(rawXOAUTH2Token, ImapAuthenticationMethod.OAuth20);

also, another question is, does ComponentPro supports connecting to Office 365 using OAuth2.0? if yes, then why there is the following summary for Enum  'ImapAuthenticationMethod.OAuth20'?

        //
        // Summary:
        //     OAuth 2.0 authentication defined by https://developers.google.com/google-apps/gmail/xoauth2_protocol#imap_protocol_exchange

Cheers,

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