I have a Suitelet script that is called by our SuiteCommerce sites, this has been working fine for years. However now the script is returning a 500 error. The response HTML includes this message: "You are not allowed to navigate directly to this page." This is a Suite Script 1.0 script. Any ideas on what to check?

sounds like someone modified the suitelet deployment to no longer be available without login

Indeed logging in works. I'll check the deployment again. And that was the issue, thanks again.