The lights in the rabbitry need to be kept on for 14-16 hours a day. The short days of winter will tell your does that it is not the right time of year to breed.
You can also try swapping the buck and doe's cage for a day. Housing the doe right next to the buck also helps. If my does won't breed they go for a ride to the next show that I go to. That gets them raring to go when they get home. A ride in the car while you are doing errands also helps. I have also heard adding a small amount of apple cider vinegar to their water works although I have never tried it.
Good Luck
Roger