Is your internet cutting out? We don’t support resumable downloads from the browser. The forbidden error happens when you try to access a download URL after it has already expired. Once you start a download from the site you’ll have to finish it in one go. If it fails, then you’ll have to go back to the project page an initiate a new download. You can not resume the download from your browser’s download tab. If you’re having trouble getting it downloaded in one go then I recommend sticking with the app.
(We do this to prevent people abusing our hosting and trying to distribute direct download links without giving credit)
Hope that helps!