The contact rented a 2021 Nissan Altima. The contact stated while driving 45 MPH, the brake pedal was depressed, and the vehicle failed to respond. There were no warning lights illuminated. The contact stated that it felt like the brakes were inoperable. The vehicle was then taken back to the rental car agency. The vehicle was not diagnosed, and the contact was unsure if the vehicle was repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 44,794. The VIN was not available.