AutoItX.Send("{ENTER}") not working

[Prosenjit]

I am new to AutoItX. I want to download and save an excel file with the help AutoItX. After clicking the download button I get a window pop up with save and cancel option. I just want to press enter to save the file. The code I am using activates the window save option is not getting clicked after using AutoItX.Send("{ENTER}"). Instead in the code it presses and enter. Below is the code I am using :

PageInstance.ButtonTemplate.Click(); //Clicks the download button
            WaitMoment(5);
            AutoItX.WinActivate("Save As");
            Thread.Sleep(2000);
            AutoItX.Send("{ENTER}");// In this line enter is getting pressed and the code gets shifted to a new line