Rabbit question

I sold a young female rabbit to my sister. I had bred this girl a couple times with no issues. Now my sister has her she won't catch. What could be the problem. The buck was born in May if I remember right. He has not been proven and is a purebred Flemish giant

It is about the most difficult time of year to breed, that is why. Wait until the day start to get significantly longer and "bingo"

ok thanks I will tell her that!