iOS App Payment Gateway Transition

We have a app in that app we have issue in deployed app on ios. We are using the cashfree and they flag that as issue. So we need to move apple payment gateway... Hello, Thanks for your time on the phone today. Guideline 3.1.1 - Business - Payments - In-App Purchase Issue Description We noticed that the app still includes or accesses paid digital content, services, or functionality by means other than In-App Purchase, which is not appropriate for the App Store. Specifically: - The app accesses digital content purchased outside the app, such as paid plans, but that content isn't available to purchase using In-App Purchase. Apps on the United States storefront may link out to the default browser, using buttons, external links, or other calls to action, for payment mechanisms other than in-app purchase. To learn more, see the News post on Apple Developer. For storefronts where there are not alternative options for qualifying apps, the app must use in-app purchase. Next Steps The paid digital content, services, or subscriptions included in or accessed by the app must be available for purchase in the app using In-App Purchase. We hope you will consider making the necessary changes to follow the App Store Review Guidelines and will resubmit your revised binary. If you need further assistance, please use App Store Connect or the Contact Us for App Review. For general information on the technical, content and design criteria used to review apps, visit App Review.