Hello Selexa,
thanks for taking your time to report a bug! I tried reproducing the issue you described, but I couldn't spot any issues with the crafting. This is what I did: I gathered a stone and branches. Then I crafted myself some fiber and learned the "Tools" skill and selected the axe. After dragging a stone on the red question mark as well as fiber on the next question mark I was able to learn the recipe. After double clicking the axe preview I crafted the Axe without issues. Did you do something differently or did I misunderstood your issue? On our store page you can see this video showing the process, which part is not working for you?
I hope my description and this video can help narrow down the issue! Thanks for playing our game and hopefully there won't be any further issues!
Have a great day :)