Hi, there's two things going on here that may be the cause. Firstly, itch.io produces a pop up to start the download, you could have the download getting blocked by your web browser.
However I'm also having an issue with the security certificate on my website at the moment, which is also causing browsers to give an error when trying to connect to the site...I'm working on that now, and will update once that side should be working without issue.