接口传参

{

  "notify_type": 2002,

  "openid": "ogPae4nWL8y29HSssBCL49MCPUUQ",

  "notify_code": "4200002213202404164459019675",

  "check_json":"{\"pay_amount\":100,\"pay_time\":1713250100}",

  "content_json":"{\"cur_status\":1,\"product_count\":1,\"wxa_path_query\":\"/pages/coupon/coupon-user/coupon-user\",\"product_list\":{\"info_list\":[{\"product_img\":\"https://www.ghxtd.com/api/pic/mini/index/icon/logo.png\",\"product_name\":\"测试券\",\"product_path_query\":\"/pages/coupon/coupon-user/coupon-user\"}]}}"

} 

返回说check_json不合法 ，是什么原因