Here is what I found sorting out a RT V-56. Don't know how close the 44 mech. is to the large door unit. Jim?
Get a strong flash-light and some heavy duty pipe cleaners and clear any dirt/obstruction from each coin path.
On mine (plate on top) facing the vend handle .25 goes in the far slot then .10. Next slot needs two nickels to allow the vend process. I'm not sure what goes on with the next two slots. Suspect one is for pennys.
Once I sorted out the machine was set for 10 cent vend and put the coin/s in the correct slot all was well. It will not allow vend if a quarter is inserted and the nickel change tube is empty.
Hope this helps. If anyone knows where service manuals for slug rejectors and coin mechs are for sale I would be a customer.