pingback returns "The order is Invalid!"

I'm following the instructions here:https://docs.paymentwall.com/modules/woocommerce
The request URL is:
https://myside.com/?wc-api=paymentwall_gateway&action=ipn&uid=1&goodsid=1231&slength=3&speriod=&type=0&ref=&is_test=1&sig=3243u2hfrie2d6f34erffeweww94h324f43243ee75

No matter how I change the goodsid (the real id or not), the Response always "The order is Invalid!"

Any ideas?