I get access_token by this way :https://developers.google.com/android-publisher/authorization
1.use google account allow acess get code
2.use code to get refresh_token
3.use refresh_token get access_token
when use this api
$url_purchase = "https://www.googleapis.com/androidpublisher/v1.1/applications".
"/$packageName/inapp/$productId/purchases/$token?access_token=".
$return_data->access_token;
$return_purchase = http_get($url_purchase);
some billing return
{"error":{"code":500,"message":null}}
some billing return
{"error":{"errors":[{"domain":"global","reason":"invalid","message":"Invalid Value"}],"code":400,"message":"Invalid Value"}}
but some billing can success return
{"kind":"androidpublisher#inappPurchase","purchaseTime":"1395035642794","purchaseState":0,"consumptionState":1}
I think the access_token is right, why some billing failed . someone can help me ?thanks very much.
Are there any other way to check billing valid on the server?