Rodger,
Larry's suggestion is the proper way to close the door if your coach is equipped with a Posi-lock door latch, however Monaco stopped using the Posi-lock feature on some of the latter model coaches because of expense.
So if your coach does not have a Posi-lock latch, you will have to determine the problem with with your linkage, and repair as necessary. Sometimes the screws that hold the top pivot in the door are stripped or loose, sometimes the rivet in the center of the scissor linkage is loose and letting the detents bypass their stop, or the detents can be worn or damaged where replacement or fabrication becomes necessary.
There is a possibility that your coach has a Posi-lock latch that is malfunctioning also. If that is the case,you will have to determine the problem (usually a broken cable), and repair or replace as necessary. As you can see, your problem is not a "one size fits all" issue, so it will take some investigation and possibly, but not necessarily, some expertise to repair.
Gerald