While driving the vehicle ahead brake suddenly. When I applied the brake pedal, it felt abnormally stiff/stuck and did not provide Norma breaking response. Th vehicle did not decelerate as expected despite immediate pedal input. At the same time, the Forward Collision Avoidance Assist system did not activate or provide any braking assistance. Due to the lack of effective braking, I was unable to stop in time and a collision occurred. The primary concern is a potential failure or malfunction in the braking system occurring prior to impact combined with the apparent failure of the automatic emergency braking system to engage. This created a situation where the vehicle could not be stopped under emergency conditions posing a serious safety risk