This errors happens when payments were initiated from a mobile webpage and redirected to WeChat's app to complete the purchase. WeChat will automatically block such transactions. This is because WeChat does not allow mobile WeChat Pay sessions that started in a mobile browser (outside the WeChat app) to continue in the app.
What are possible solutions to this?
In order to allow WeChat Pay transactions on a mobile platform, there are three possible solutions:
1. Apply for an official WeChat account. Your account will act as an app within WeChat and your shoppers will be able to make payments to you. Only verified service accounts are allowed to process payments. You may register for a service account on WeChatPay. Further information can be found here.
2. Integrate with Adyen’s in-app Checkout solution. Your shoppers will be able to make WeChatPay payments directly in your app. More details can be found in our WeChat Pay in-app documentation.
3. Alternatively, the merchant can opt not to show WeChat Pay payment method if the shopper is on a mobile browser, e.g (Chrome/Safari/Mozilla on iPhone/Android).