Port 8500 is not in use and have also tried changing the port in

server.xml

but I get the same error regardless of which port I use?

That error usually means that ACF is starting as a user that does not have permissions to open TCP ports if you are sure that there isn't anything else running on 8500. Try running as root just to see if it starts up. You might also be running something like SELinux that may be blocking it as well.

Hey @quetwo, thank you for your reply and sorry for the delay getting back to you, it's been a crazy week! We ended up having to restore our server from a backup which fixed the problem and still looking at the root cause. Not sure if this is standard but we get a

You must be root to start ColdFusion.

straight away if we are trying to start with insufficient privileges and this error was happening a few seconds after CF had started which then was causing it to terminate. As you suggest, I believe that it was a lower level issue, Java or Linux that was blocking ports being opened.

Java wouldn't block the ports, but if you do a default install of SELinux or have a 3rd party firewall installed that certainly could do it too.

I didn't mean to infer that Java would block the port intentionally, I meant that if a library file was corrupted or missing then it would prevent connecting. It's Centos and no firewalls on the machine 🙂

Again, base install of CentOS has SELinux installed, unless you manually uninstall it. You usually need to set the security policy/level on install. That can and will prevent ports from being opened up.

Yes but it doesn't account for the fact that it was working prior to Monday and only came to light when trying to restart CF. The OS and CF was installed 4 years ago and no recent changes to the system can account for why CF couldn't open ports. FYI the security policy is enabled but dated more than a month ago and there have been multiple restarts on CF since then. That said, thank you for the steer, I am going to boot up the backup of the failing server and compare the security policy with the current one which is working.