iOS receipt validation with apple sandbox server fails

Hi,

I’ve been testing a new build for the appstore but when trying to validate a subscription we get error code 21005 from their sandbox server. According to their status codes table, this means their server has a temp issue and we should try again. However, I’ve been trying this for the past 48h without success, so I begin to suspect they made yet another change in their validation code.
Has anyone else encountered this issue? I looked for new info on their purchase validation but couldn’t find anything.
This is probably not an issue with the latest builds, as I also encounter this on an old build that used to work fine a month ago.
Note, we’re still using the old store API with a network call to their sandbox server: “https://sandbox.itunes.apple.com/verifyReceipt

Seems to be working again after few days, so false alarm.