Buscapé API stopped returning XML

I'm trying to access the address link at browser but stopped returning the XML. The application stopped returning a few days ago, it returned the XML right in both the application and direct in the browser but for a few days I stopped returning everything, in any browser and in the application where I use it, I'm still in the development environment where I need to pass the sandbox name according to web address. Does anyone know what might have happened?