If your script attempts to make an HTTP connection to a URL on the same server then that will fail. This is because loopback connections like that are blocked on our servers because they can be exploited by attackers.

Best practise would be to not use a loopback connection to access a file on the same domain, and instead use a local include. If it isn't possible to update the script in that way then it would need to be hosted on a VPS or dedicated server rather than our shared hosting platform. You would then have full control over firewall configuration and could choose to allow HTTP loopback connections.