This issue is quite common in some cameras and the solutions can range from simple to pretty complex. Sometimes the reason a camera's flash will not work is because the battery is already running low to the point where the camera can no longer produce a flash. To resolve this all you would need to do is replace the batteries. If that is not the case and your flash is still not working, then there may be a defective flash circuit in which you will need to plan out an exchange with the company you have purchased the camera if it is still under warranty. Hope this helps!