C# 中的 Microsoft Graph“访问被拒绝。检查凭据并重试”

Question

This is my code to get emails from my email account through Microsoft Graph, but I keep getting an error regardless on credentials.

Code:

var scopes = new[] { "https://graph.microsoft.com/.default" };
var tenantId = "";
var clientId = "";
var clientSecret = "";

var clientSecretCredential = new ClientSecretCredential(
    tenantId, clientId, clientSecret);
var graphClient = new GraphServiceClient(clientSecretCredential, scopes);
var inboxMessages = await graphClient
                        .Users["email"]
                        .MailFolders["inbox"]
                        .Messages
                        .Request()
                        .Expand("attachments")
                        .Top(20)
                        .GetAsync();
Console.WriteLine(inboxMessages);
Console.ReadLine();

Error:

Permissions:

Answer 1

In the client credential flow there won't be any user authentication, so delegated permissions doesn't work. Please give application permissions in the API permissions in azure ad.

There are two types of permissions. Application permissions and delegated permissions. Here if you have a user logging into the app then you would use a different flow and you can use these delegated permissions. But here there is no user as it's a client credential flow. So use application permissions to make the above code work.