According to Home Repair Central, a door strike plate needs to be adjusted if it does not align properly with the door lock. You may need to move the strike plate slightly in or out to match the door lock correctly.
Adjust the door plate if the setting needs to be snugged up
Move the strike plate towards the center of the door jamb if the door needs to be tightened. Use a screwdriver to loosen the screws slightly in the door's strike plate. To protect the surface of the door, use a hammer and a block of wood to tap the strike plate gently in the right direction. The exterior door should be snug up against the weatherstripping.
Adjust the door plate if the setting needs to be tightened slightly
Move the strike plate away from the center of the door jamb if the strike plate does not sit properly when the door is closed. Use the hammer and the block of wood to move the strike plate, and tighten the screws with the screwdriver.
Check the door
After adjusting the strike plate, open and close the door to make sure that the door can close and latches properly.