How can I get an Access Token by application without providing password but silently?

Question

Hello,

I am wondering to retrieve access token silently but not providing the password.

Is that is a way to do so?

Answer 1

I am also trying to get this working.
Here is my code:

var opt = new ConfidentialClientApplicationOptions()
{
    ClientId = "xxx_clientid",
    TenantId = "xx_tenant_id",
    ClientSecret = "xxx_client_secret_value",
    RedirectUri = "http://localhost",
};

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.Send", // Only needed for SMTP
};

var app = ConfidentialClientApplicationBuilder.CreateWithApplicationOptions(opt).Build();
var authToken = await app.AcquireTokenForClient(scopes).ExecuteAsync(); // <--- Exception
var oauth2 = new SaslMechanismOAuth2(authToken.Account.Username, authToken.AccessToken);

using (var client = new ImapClient(new ProtocolLogger("imapLog.txt")))
{
    client.Connect("outlook.office365.com", 993, SecureSocketOptions.SslOnConnect);
    //client.AuthenticationMechanisms.Remove("XOAUTH2");
    client.Authenticate(oauth2);
    var inbox = client.Inbox;
    inbox.Open(MailKit.FolderAccess.ReadOnly);
    Console.WriteLine("Total messages: {0}", inbox.Count);
    Console.WriteLine("Recent messages: {0}", inbox.Recent);
    client.Disconnect(true);
}

Running the code I get this exception:

Microsoft.Identity.Client.MsalServiceException: 'AADSTS70011: The provided request must include a 'scope' input parameter. The provided value for the input parameter 'scope' is not valid. The scope email offline_access https://outlook.office.com/IMAP.AccessAsUser.All is not valid.