A couple things you can try are to relocate their nest box or give them a choice of nest boxes of different styles and materials. I always preferred the wooden boxes and had good luck with them. A change of lighting and cage location might help. Consider trying to make their cage more private or...
Deep RED?? That sounds like a male as males can be blue or bright pink. A female is full breeding mode will have a dark BROWN cere; and not all females get that dark of brown.
Two males will bond and seem much like a true pair.