If you see this error while trying to run “Check for Updates” in PixInsight, there is some aspect of your internet connection configuration blocking access to the RC Astro content delivery site, rc-astro-cdn.com. It could be a firewall, a proxy, virus/malware protection software, or your Internet Service Provider.

If it is your ISP, you may need to contact them to unblock access to the site: check their website for instructions.

Also check your operating system’s network configuration: your machine may have a problem with secure HTTP connections.