No, no other site. Read at the top of the download page though:
"If you are experiencing trouble downloading, it could be due to an ad-blocker or extension in your Chrome browser.
Try whitelisting
www.subsim.com in your ad-blocker extension, or switching to Microsoft Edge browser or Firefox to complete the download. Thanks."
That is the most likely reason. Change browsers, or "whitelist" this site in your current browser.
