Problems with P. machaon

Yesterday I got a beautiful big pair of Papilio machaon. I waited until this morning and handpaired them with succes, they split after 1,5h. Of course I was feeding them, I gave a sugar - water solution. I gave the females some wild carrot, but she doesn't want to lay any eggs! It's really strange as machaon is one of the easiest butterfly to get eggs from. I was trying different methodes - 'hot box' in aquarium and cage (however, she was just sitting and sometimes catching the light), I was also putting her just on carrot with my hand and waiting. Sometimes she was fluttering her wiings, but then she stopped and spreaded her wing.
What's the problem? For sure she was fertillized. Is she waiting a few days more to develop her eggs? I had a female 2 years ago that laid over 50 eggs a while ater mating within several minutes. I really don't understand her...