请问一下，微信小游戏虚拟支付 沙箱环境 获取游戏币余额（midas.getBalance），一直返回-1 系统繁忙，怎么回事？
json串：
{"openid":"o7DGb5Qu8PtpQmauuFAevpx8DZfc","appid":"wx4cd5530db322ee1f","offer_id":"1450024169","ts":1586232820968,"zone_id":"1","pf":"android","sig":"cc6fc59b617e166b0f8cf16bdc536135641c71daf737676763aac2150c6b9f02","mp_sig":"8c5d31f12767a597ebf4b7cdc23a4dd25cead0a8572c2fd6ea4085e937fc6a4d"}
麻烦提供下完整请求以及返回信息，查余额没有日志信息，或调笔赠送看下 。
post json数据：{"openid":"o7DGb5Qu8PtpQmauuFAevpx8DZfc","appid":"wx4cd5530db322ee1f","offer_id":"1450024169","ts":1586232820968,"zone_id":"1","pf":"android","sig":"cc6fc59b617e166b0f8cf16bdc536135641c71daf737676763aac2150c6b9f02","mp_sig":"8c5d31f12767a597ebf4b7cdc23a4dd25cead0a8572c2fd6ea4085e937fc6a4d"}
获取游戏币余额失败：code：-1
url:https://api.weixin.qq.com/cgi-bin/midas/sandbox/getbalance?access_token=32_IjMhkHyIXFAqAsOMWKmktO1XpYE-gwGVhuewyfXEjytVbOEZwNF6nvTwxsC2j3oMLjGACnr_RDzjanVBXq8hyzOj8rEOGrl76hgKdmnGCvlm-l9pWp8y8xkBipcfK4L8RnvPHelN-CoFGEQTQGMiAAAZPV
post json数据：{"openid":"o7DGb5Qu8PtpQmauuFAevpx8DZfc","appid":"wx4cd5530db322ee1f","offer_id":"1450024169","ts":1586232820968,"zone_id":"1","pf":"android","sig":"cc6fc59b617e166b0f8cf16bdc536135641c71daf737676763aac2150c6b9f02","mp_sig":"8c5d31f12767a597ebf4b7cdc23a4dd25cead0a8572c2fd6ea4085e937fc6a4d"}
获取游戏币余额失败：code：-1