var
    fIdSSLIOHandlerSocket: TIdSSLIOHandlerSocketOpenSSL;
    fIdSMTP: TIdSMTP;
    fIdMessage: TIdMessage;
begin
  fIdSMTP := TIdSMTP.Create(nil);
  fIdSSLIOHandlerSocket := TIdSSLIOHandlerSocketOpenSSL.Create(fIdSMTP);
  fIdSSLIOHandlerSocket.SSLOptions.Method := sslvTLSv1_2; //sslvTLSv1
  fIdSSLIOHandlerSocket.SSLOptions.Mode:= sslmUnassigned;
  fIdSMTP.IOHandler:= fIdSSLIOHandlerSocket;
  fIdSMTP.ConnectTimeout:= 5000;
  fIdSMTP.UseTLS := utUseImplicitTLS; //utUseExplicitTLS

  with fIdSMTP do
  begin
    Host := 'smtp.office365.com';
    Port := 587;
    AuthType := satDefault; //atLogin;
    Username := aEmailParam.EmailUserName;
    Password := aEmailParam.EmailPassword;

    HeloName := 'fto';
  end;

  //Формируем письмо для отправки
  fIdMessage := TIdMessage.Create(nil);
  try
    with fIdMessage do
    begin
      Body.Text := aBodyEng;
      From.Text := aEmailParam.EmailUserName;
      Recipients.EMailAddresses := aRecipients;
      Subject := aSubject;
    end;

    //отправляем сообщение
    if not fIdSMTP.Connected then
    begin
      try
        fIdSMTP.Connect;
      except
        on E: Exception do
          ResStr := ResStr + E.Message;
      end;
    end;

    try
      if fIdSMTP.Connected then
      begin
        fIdSMTP.Send(fIdMessage);
        Result := true;
      end;
    finally
      fIdSMTP.Disconnect;
    end;

  finally
    FreeAndNil(fIdMessage);
  end;

  if assigned(fIdSSLIOHandlerSocket) then
    FreeAndNil(fIdSSLIOHandlerSocket);
  if assigned(fIdSMTP) then
    FreeAndNil(fIdSMTP);