Could you please add ‘allow-download’ attribute to your sandboxed iframe? Right now we have issues posting link to download files.
Chrome says “Download is disallowed. The frame initiating or instantiating the download is sandboxed, but the flag ‘allow-downloads’ is not set. See https://www.chromestatus.com/feature/5706745674465280 for more details.”
BTW, we are posting link to the page with download links, not the file link itself. It’s strange behavior, but our users are suffering from it.