NullReferenceObject error with raycast

I have this script that when a raycast points at a door and i hit E i enter the door. The script works but everytime my camera doesn’t point at a door i get a nullreference exception.

     // Cast a ray to see what the camera is looking at.
            Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            RaycastHit hit;
            if (Physics.Raycast(ray, out hit)) ;
            {
                // Find the door associated with the hit collider.
               GameObject doorObj = GameObjectUtils.FindObjectWithTagUpHeirarchy(hit.collider.gameObject, "Door");
                if (doorObj) ;
                { 
                 if (hit.collider == doorObj) ;
                    {
                        var doorComponent = doorObj.GetComponent<DoorComponent>();

                        interactTextObj.SetActive(true);

                        if (doorComponent.leadsToAnotherCell)
                        {
                            interactTextObj.GetComponent<Text>().text = doorComponent.doorExitName;
                        }
                        else
                        {
                            interactTextObj.GetComponent<Text>().text = doorComponent.doorName;
                        }

                        if (Input.GetKeyDown(KeyCode.E))
                        {
                            OpenDoor(doorComponent);
                        }

                    }  
                }
            }

I just removed “if (hit.collider == doorObj) ;” and it works!