Promotional codes for our spheres

Hello there
I am trying to create promotions for my spheres and when I create the promotion in google play console it tells me to verify if my application has integrated the billing library of google play and I think that when the .aab is generated from the wacht face studio program it does not implement it

When I have created the promotion and activated I try to redeem a code and I get the error that the code has not worked

Do you know how this problem can be solved or where I have to configure so that the codes can be fixed?

Google Play Billing library is not integrated in WFS.
You can check out the Create promotions - Play Console Help guide to know details about promotion creation.
Thank you.