What is the ruling on working in an internet café where some customers open pornographic websites, and does the sin fall away from the worker if he informs the customer to stop that, knowing that individuals under the age of maturity are prohibited from doing so?

It is permissible to open an internet cafe and work in it if the matter is controlled by the Sharia guidelines, by preventing visitors from accessing pornographic websites and using the internet for forbidden acts. Merely informing and advising them is not enough; rather, they must be expelled, especially the adults among them.