https://api.mch.weixin.qq.com/v3/marketing/favor/coupon-stocks

返回：{"code":"SYSTEM_ERROR","message":"系统繁忙，请稍后重试"}

修改参数的话，会返回准确的错误提示，但是调好参数后就变成报这个错，不知道怎么定位问题

参数：

{"stock_name":"一元代金券","comment":"一元代金券","belong_merchant":"1518800391","available_begin_time":"2019-10-09T13:29:35.120+08:00","available_end_time":"2019-10-20T13:29:35.120+08:00","stock_use_rule":{"max_coupons":100,"max_amount":5000,"max_amount_by_day":100,"max_coupons_per_user":3,"natural_person_limit":false,"prevent_api_abuse":false},"pattern_info":{"description":"","merchant_logo":"","merchant_name":"","background_color":"","coupon_image ":""},"coupon_use_rule":{"coupon_available_time":{"fix_available_time":{"available_week_day":[1,2,3,4,5,6,0],"begin_time":0,"end_time":86400},"second_day_available":false,"available_time_after_receive":60},"fixed_normal_coupon":{"coupon_amount":100,"transaction_minimum":110},"goods_tag":"123321,123322","trade_type":["APPPAY","OTHER"],"combine_use":false,"available_items":[],"unavailable_items":[]},"no_cash":true,"stock_type":"NORMAL","out_request_no":"1518800391201910081570517091"}