Call of duty modern warfare 4 multiplayer server login error (Call of Duty 4: Modern Warfare)

hey dude i have the same problem

What to do, in the last mission where we are driving on the bridge with Price, Griggs and Gus from the mi-24, then when we drive onto the bridge and at the moment when we drive in, the helicopter shell hits the car and the mission is bugged and starts all over again from the beginning of the departure from mi-24 and so on ad infinitum