为什么Delphi编写的邮件程序不能发qq邮件，126、163邮箱都可以发送！各位高手帮帮忙。。。。

我的源代码：
我得源代码：

type
TForm1 = class(TForm)
edt1: TEdit;
edt3: TEdit;
lbl1: TLabel;
lbl3: TLabel;
edt4: TEdit;
lbl4: TLabel;
ListBox1: TListBox;
lbl5: TLabel;
lbl6: TLabel;
Memo1: TMemo;
lbl7: TLabel;
lbl8: TLabel;
edt5: TEdit;
edt6: TEdit;
btn1: TButton;
btn2: TButton;
OpenDialog1: TOpenDialog;
IdSMTP1: TIdSMTP;
IdMessage1: TIdMessage;
edt7: TEdit;
lbl9: TLabel;
IdSASLLogin1: TIdSASLLogin;
IdUserPassProvider1: TIdUserPassProvider;
lbl2: TLabel;
edt2: TEdit;
procedure btn2Click(Sender: TObject);
procedure btn1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var Form1: TForm1;
implementation
{$R *.dfm}uses IdAttachmentFile;
procedure TForm1.btn1Click(Sender: TObject);
begin
if OpenDialog1.Execute then
ListBox1.Items.Add(OpenDialog1.FileName);
end;

procedure TForm1.btn2Click(Sender: TObject);
var
filename:string;
begin
try
IdSMTP1.AuthType :=satSASL; //设置登录类型
IdUserPassProvider1.Username :=edt5.Text ; //设置登陆帐号
IdUserPassProvider1.Password :=edt7.Text; //设置登陆密码
IdSMTP1.Host:=edt1.text; //设置SMTP地址
filename := OpenDialog1.FileName ; //需要添加的附件文件
TIdAttachmentFile.Create(IdMessage1.MessageParts,filename); //添加附件
IdSMTP1.Port:=25; //设置端口 必须转化为整型 delphi2006不需要用
if not idsmtp1.Connected then
IdSMTP1.Connect; //开始连接服务器
except
Showmessage('连接失败,请重试!');
Exit; //连接失败 的话 退出该执行过程
end;
IdMessage1.Body.Clear; //先清空上次发送的内容
IdMessage1.Subject:=edt4.Text; //设置邮件发送的标题
IdMessage1.Body.Assign(Memo1.Lines); //设置邮件发送的主体
IdMessage1.CharSet := 'gb2312';
IdMessage1.From.Address:=edt6.Text; //设置邮件的发件人 也就是说该邮件来自什么地方 //
IdMessage1.Recipients.EMailAddresses:=edt3.Text; //收件人的地址
IdMessage1.CCList.EMailAddresses:=edt2.Text;//抄送
//IdMessage1.BccList.EmailAddresses:=''; //密送
IdMessage1.Priority:=mpHighest; //邮件重要性
try
IdSMTP1.SASLMechanisms.Add;
idSMTP1.Send(IdMessage1);
Showmessage('邮件发送成功!');
except
Showmessage('邮件发送失败!');
end;
end;
end.

进QQ邮件 然后设置 开启smtp服务

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