Promotional Offer keeps returning Contact Developer (Error code: 3903)

I am trying to add promotional offers in my iOS App. The signature is being verified through a google cloud function. My user id, signature, and product and offerIds return perfect. Promotional offer appears in the payment sheet as well. When applying for payment, the "ding" sound comes as well. But then I get the UIAlert with Unable to Purchase Contact developer. Error code in logs is 3903

Promotional Offer keeps returning Contact Developer (Error code: 3903)
 
 
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