Thanks. adding -ld64 flag also fixed our deploy issue. 👍🏻 But could somebody please explain what this flag is and what it does?

@Heps I am facing the same issue. App Store build works just fine, but once I deploy and debug directly on the device, it fails with same error 4 like you are getting. And we haven't changed the code related to this at all.

Hi, we are currently facing exactly the same error on an iPhone 12 with iOS 14.5. It used to work just fine the past few days and weeks. But suddenly today, when trying to invoke DCAppAttestService.shared.attestKey() we are also getting the same error: Error Domain=com.apple.devicecheck.error Code=0 Are there any tips on how to solve this issue?