WeChat payment does not call back

In the process of using the project, it was found that WeChat payment was a callback, and no problems were found in the code.
Finally, it was found that it did not conform to WeChat specifications.
WeChat requires the callback address, which must conform to the payment path configured on the public platform.
For example, if
the configuration path of the public platform is:
www.xxx.com/pay
, the callback path must be an address starting with www.xxx.com/pay/:
www.xxx.com/pay/paytype1

www.xxx.com/pay/paytype2