错误403尝试使用Apis获取邮件列表（Gmail）和任务（Google任务）

Question

我正在使用VB.Net，我按照说明从Google获取消息列表（gmail api v1）和任务（任务api v1）：

https://developers.google.com/gmail/api/v1/reference/users/messages/list https://developers.google.com/google-apps/tasks/v1/reference/tasks/list

但我收到错误403（权限不足），但我的datagridview填充了以下带有空单元格的标题：

的Gmail：

HistoryId - Id - LabelIds - Payloads - Raw - SizeEstimate - Snippet - ThreadId - Etag

任务：

Etag - Items - Kind - NextPageToken

我查看了我的google开发者控制台，一切顺利，api已激活。

我也使用我的xxxxxxxxx@developer.gserviceaccount.com（以防万一）。

另请按照云端硬盘和日历api的说明操作，这些工作正常，但任务和Gmail给我这个问题。

我使用凭证（客户端ID和客户端密码）进入。

我试过Google api资源管理器，一切正常。

如何解决此错误？

以下是我的任务和Gmail代码：

        Imports Google.Apis.Auth.OAuth2
    Imports Google.Apis.Services
    Imports Google.Apis.Tasks.v1
    Imports Google.Apis.Tasks.v1.Data.Tasks
    Imports Google.Apis.Tasks.v1.Data
    Imports System.Collections.Generic
    Imports Google.Apis.Util.Store
    Imports System.Threading
    Imports System
    Public Class Form1
        Dim Secrets = New ClientSecrets()
        Dim scope = New List(Of String)
        Dim initializer = New BaseClientService.Initializer
        Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
            Secrets.ClientId = "MY CLIENT ID"
            Secrets.ClientSecret = "MY CLIENT SECRET"
        End Sub
        Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
            scope.Add(TasksService.Scope.Tasks)
            Try
                Dim credential = GoogleWebAuthorizationBroker.AuthorizeAsync(Secrets, scope, "My Gmail account or developer account &.GOOGLE.COM", CancellationToken.None).Result()
                initializer.HttpClientInitializer = credential
                initializer.ApplicationName = "APP NAME"
                Dim service = New TasksService(initializer)
                Me.DataGridView1.DataSource = retrieveAllTasks(service)
            Catch ex As Exception
                MsgBox(ex.ToString)
            End Try
        End Sub
        Public Shared Function retrieveAllTasks(service As TasksService) As List(Of Tasks)
            Dim result As New List(Of Tasks)()
            Dim request As TasksResource.ListRequest = service.Tasks.List("@default")
            Do
                Try
                    Dim Gtasks As Tasks = request.Execute()
                    result.AddRange(Gtasks.Items)
                    request.PageToken = Gtasks.NextPageToken
                Catch ex As Exception
                    MsgBox(ex.ToString)
                    request.PageToken = Nothing
                End Try
            Loop While Not [String].IsNullOrEmpty(request.PageToken)
            Return result
        End Function
    End Class


   Imports Google.Apis.Auth.OAuth2
Imports Google.Apis.Services
Imports Google.Apis.Tasks.v1
Imports Google.Apis.Tasks.v1.Data.Tasks
Imports Google.Apis.Tasks.v1.Data
Imports System.Collections.Generic
Imports Google.Apis.Util.Store
Imports System.Threading
Imports System
Imports Google.Apis.Gmail.v1
Imports Google.Apis.Gmail.v1.Data

Public Class Form1
    Dim Secrets = New ClientSecrets()
    Dim scope = New List(Of String)
    Dim initializer = New BaseClientService.Initializer
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Secrets.ClientId = "CLIENT ID"
        Secrets.ClientSecret = "CLIENT SECRET"
    End Sub

    Public Shared Function ListMessages(service As GmailService) As List(Of Message)
        Dim result As New List(Of Message)()
        Dim request As UsersResource.MessagesResource.ListRequest = service.Users.Messages.List("TARGET EMAIL")
        Do
            Try
                Dim response As ListMessagesResponse = request.Execute()
                result.AddRange(response.Messages)
                request.PageToken = response.NextPageToken
            Catch ex As Exception
                MsgBox(ex.ToString)
            End Try
        Loop While Not [String].IsNullOrEmpty(request.PageToken)
        Return result
    End Function
    Private Sub Button10_Click(sender As Object, e As EventArgs) Handles Button10.Click
        Try
            scope.Add(GmailService.Scope.MailGoogleCom)
            Dim credential = GoogleWebAuthorizationBroker.AuthorizeAsync(Secrets, scope, "XXXXXXXX@developer.gserviceaccount.google.com", CancellationToken.None).Result()
            initializer.HttpClientInitializer = credential
            initializer.ApplicationName = "APP NAME"
            Dim service = New GmailService(initializer)
            Me.DataGridView1.DataSource = ListMessages(service)
        Catch ex As Exception
            MsgBox(ex.ToString)
        End Try
    End Sub
End Class