The Zinc Bee requires a Tin Bee to be bred. However in a mod that adds zinc but not tin (such as Create), breeding a zinc bee is impossible

Didn't think a mod would add zinc without tin. I'll change it for the next version.
Until then you can change the recipe with a datapack if you can't wait. The recipe is here https://github.com/JDKDigital/productive-bees/blob/master/src/main/resources/data/productivebees/recipes/bee_breeding/zinc_bee.json

Recipe has been changed