System.InvalidOperationException: No web service found at: /SnCoreWeb/ScriptServices.asmx

I've been trying to (re)enable a service to be called from JavaScript without any luck. I try to hit http://localhost/SnCoreWeb/ScriptServices.asmx, that works, but http://localhost/SnCoreWeb/ScriptServices.asmx/js doesn't with the following error.

Exception Details: System.InvalidOperationException: No web service found at: /SnCoreWeb/ScriptServices.asmx.





[InvalidOperationException: No web service found at: /SnCoreWeb/ScriptServices.asmx.]
System.Web.Script.Services.WebServiceData.GetWebServiceData(HttpContext context, String virtualPath, Boolean failIfNoData, Boolean pageMethods) +817
System.Web.Script.Services.WebServiceClientProxyGenerator.GetClientProxyScript(HttpContext context) +49
System.Web.Script.Services.RestClientProxyHandl ...