Depending on which model grill you own, a quick and easy fix with the adjustable door hinges should do the trick!
The adjustable door hinges can slide the doors to the left and right or up and down to line up the doors.
Move the door to the proper position. While holding it there, tighten the adjustable door hinge on the lower corner (it should be just under the door you are adjusting).
More information on adjusting the doors can be found in your assembly guide. To download your assembly guide please click here.
If that does not fix the situation, examine the doors and make sure there aren't any bends or dents that may have prevented the doors from lining up.