Unreal Engine 5 In-game Payment Troubleshoot

Job ID: 39540251

Budget: $10 – $120 USD

Making a real-world payment from Unreal Engine 5 using XSOLLA
I'm trying to make a real-world payment of 0.25 USD, or 5 MXN, but I'm getting an error message saying 0401-1102: Unprocessable entity. I'm thinking it's because some data isn't reaching the Fetch payment token function, as shown in the video. Free purchases work fine. Purchases from the Web Shop work, but I want to do it directly from the game. The job would be complete once I successfully make an in-game payment.
This is the web shop:
https://escape-area-51.xsolla.site/

XSOLLA told me that making a payment requires a payment token to authorize the user and is a key component of the Xsolla process to prevent fraudulent payments. The payment token contains encrypted data about the game and the user and is used to identify the user and enable the purchase. This token is generated after passing the necessary user and ordering information to the XSolla API. It is then used to open the payment interface and securely process the transaction.
The more relevant data you provide in the token, the more effective the anti-fraud measures will be. Without a valid payment token, the payment process cannot continue and anti-fraud checks cannot be properly applied.

https://developers.xsolla.com/doc/pay-station/how-to/how-to-get-payment-token/#pay_station_how_to_get_payment_token

I only have the maximum budget indicated. I do not accept proposals outside the maximum.