Not able to download the excel file in Windows popup using AutoIT

[IMLearner]

Not able to download the excel file in Windows popup using AutoIT .
Iam not getting any error message.
Please guide me what mistake iam doing.
I have manage to open and reach upto that page where it gives the popup asking for options – “open” or “Save” and with “OK” button at the bottom.
But, after this nothing is happening and iam stuck.
I need to click on “OK” button(as it is by default “Save File” radio button is selected).

Thanks