HTTPS on IIS File Download Error

Hello,
I’ve moved my Drupal website from Apache to IIS.
I made the adjustment needed for the web.config as specified here:
Clean Url

I made it work and I can navigate any page normally, however when I try to download and file I have a 404 error file not found.
It seems the Clean Url only fails on files download.

What doe I do wrong?

Thanks,
Gaetano

Drupal version: 


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