do you have any other females? if so i noticed when replacing a female with some "fresh meat" it gets the male all excited and starts "breeding" everyone. So whenever i need a male to get on the ball i throw in a new female and it does the trick.
Ive only done this with males that have bred before.
It also could be the male. I have a male that used to be a pet and he refuses to breed his new name is food. Also if your not sure about his past he could have been a retired breeder. Depending on age he may not be interested in females. I have a few males i need to get rid of that have done their jobs and no longer have interest in breeding.

Cliffs notes: try a new male