檢查一下你送的URL對不對
sandbox跟production要送不一樣的URL
What url should I use to verify my receipt ?
Use the sandbox URL https://sandbox.itunes.apple.com/verifyReceipt while testing your application in the sandbox and while your application is in review.
Use the production URL https://buy.itunes.apple.com/verifyReceipt once your application is live in the App Store.
https://developer.apple.com/library/ios/technotes/tn2259/_index.html#//apple_ref/doc/uid/DTS40009578-CH1-FREQUENTLY_ASKED_QUESTIONS

我是送到sandbox去做測試

error code?

21002不過改用google的插件 postman 可以驗證成功

http POST 的 content-type 要指定 application/json