gistfile1.txt

          var options = new PublicClientApplicationOptions
            {
                ClientId = "ClientId",
                TenantId = "TenantId",
                RedirectUri = "https://login.microsoftonline.com/common/oauth2/nativeclient",
                AzureCloudInstance = AzureCloudInstance.AzurePublic
            };

            var publicClientApplication = PublicClientApplicationBuilder.CreateWithApplicationOptions(options).Build();
            //TokenCacheHelper.EnableSerialization(publicClientApplication.UserTokenCache);

            var accounts = await publicClientApplication.GetAccountsAsync();

            var scopes = new string[] {
                "email",
                "offline_access",
                "https://outlook.office.com/IMAP.AccessAsUser.All", // Only needed for IMAP
                //"https://outlook.office.com/POP.AccessAsUser.All",  // Only needed for POP
                //"https://outlook.office.com/SMTP.AccessAsUser.All", // Only needed for SMTP
            };

            var firstAccount = accounts.FirstOrDefault();
            AuthenticationResult authToken = null;

            try
            {
                authToken = await publicClientApplication.AcquireTokenSilent(scopes, accounts.FirstOrDefault()).ExecuteAsync();
            }
            catch (MsalUiRequiredException)
            {
                try
                {
                    authToken = await publicClientApplication.AcquireTokenInteractive(scopes).ExecuteAsync(); // HANGING AFTER FIRST SUCCESS CONNECTION
                }
                catch (MsalException msalex)
                {
                    Console.WriteLine("Error Acquiring Token:" + msalex.Message);
                }
                catch (Exception ex)
                {
                    throw ex;
                }
            }

            //var authToken = await publicClientApplication.AcquireTokenSilent(scopes, firstAccount).ExecuteAsync();
            var oauth2 = new SaslMechanismOAuth2(authToken.Account.Username, authToken.AccessToken);

            await client.DisconnectAsync(true);