How do I fix In-app purchase failed?

i have already setup all of my in-app product in construct 3 and play console like in the picture.

the product registration is success. but the are no available products to purchase and when i tried the purchase it is failed and google billing isn't show how to fix it?

You have no trigger when the purchase is successful

Mobile IAP - On product "alljobs" purchase success > add something

thank you for your reply, i've already add it.

also with on purchase failed.

i've already added it before i posted this question.

i think because i haven't add something like google billing api in play console/google cloud, but i don't know whick google api that use for in app purchase. i have add play service api to do google play login and it is success.

sory for my bad english