BOTH BACK DOORS WILL NOT CLOSE
You need to include make, model, year of the vehicle you are asking about. But generally door latches are mechanical and very simple systems. You may have moved the latch on the doors and now they are not receving the metal part of the door frame. Look to see if this latch is presenting the opening properly. There is a notch that needs to be showing. But do include car info. If no luck then a mechanic needs to be consulted. Good luck.