无法通过 Microsoft Graph API（C# 控制台）发送电子邮件

我按照这 2 个链接创建了一个控制台应用程序，用于使用 Graph API 发送电子邮件：

Microsoft Graph API 无法发送电子邮件 C# 控制台 https://stackoverflow.com/questions/57411274/microsoft-graph-api-unable-to-send-email-c-sharp-console

我已在 Azure AD 应用程序中添加并授予了所需的权限：

我确保提供了客户端 ID、租户 ID、客户端密码。

但是，我在运行控制台时看到此错误：

我缺少什么？

这是我尝试过的代码Microsoft Graph API 无法发送电子邮件 C# 控制台 https://stackoverflow.com/questions/57411274/microsoft-graph-api-unable-to-send-email-c-sharp-console

static void Main(string[] args)
    {
        // Azure AD APP
        string clientId = "<client Key Here>";
        string tenantID = "<tenant key here>";
        string clientSecret = "<client secret here>";

        Task<GraphServiceClient> callTask = Task.Run(() => SendEmail(clientId, tenantID, clientSecret));
        // Wait for it to finish
        callTask.Wait();
        // Get the result
        var astr = callTask;
    }

    public static async Task<GraphServiceClient> SendEmail(string clientId, string tenantID, string clientSecret)
    {

        var confidentialClientApplication = ConfidentialClientApplicationBuilder
            .Create(clientId)
            .WithTenantId(tenantID)
            .WithClientSecret(clientSecret)
            .Build();

        var authProvider = new ClientCredentialProvider(confidentialClientApplication);       

        var graphClient = new GraphServiceClient(authProvider);

        var message = new Message
        {
            Subject = "Meet for lunch?",
            Body = new ItemBody
            {
                ContentType = BodyType.Text,
                Content = "The new cafeteria is open."
            },
            ToRecipients = new List<Recipient>()
            {
                new Recipient
                {
                    EmailAddress = new EmailAddress
                    {
                        Address = "[email protected] /cdn-cgi/l/email-protection"
                    }
                }
            },
            CcRecipients = new List<Recipient>()
            {
                new Recipient
                {
                    EmailAddress = new EmailAddress
                    {
                        Address = "[email protected] /cdn-cgi/l/email-protection"
                    }
                }
            }
        };

        var saveToSentItems = true;

          await graphClient.Me
            .SendMail(message, saveToSentItems)
            .Request()
            .PostAsync();

        return graphClient;

    }

根据您生成的代码confidentialClientApplication， 您正在使用客户凭证提供者 https://learn.microsoft.com/en-us/graph/sdks/choose-authentication-providers?tabs=CS#ClientCredentialsProvider.

但您发送电子邮件的方式是：

await graphClient.Me
.SendMail(message, saveToSentItems)
.Request()
.PostAsync()

它在呼唤https://graph.microsoft.com/v1.0/me/sendMail实际上。

但客户端凭证流不支持/me端点。你应该打电话https://graph.microsoft.com/v1.0/users/{id | userPrincipalName}/sendMail在这种情况下的终点。

所以代码应该是：

await graphClient.Users["{id or userPrincipalName}"]
    .SendMail(message, saveToSentItems)
    .Request()
    .PostAsync();

或者如果你想使用/me/sendMail， 选择授权码提供者 https://learn.microsoft.com/en-us/graph/sdks/choose-authentication-providers?tabs=CS#AuthCodeProvider，您应该在其中实现交互式登录。

您可以了解场景和差异授权码流程 https://learn.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-auth-code-flow and 客户端凭证流程 https://learn.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-client-creds-grant-flow.