Hi, I encountered the same error after upgrading to iOS 26 and I would like to gather more information. We manage to call the API properly during the initialization of our application but after an application restart it returns this error. The API DCAppAttestService.shared.generateAssertion(keyID, clientDataHash: clientDataHash) returns com.apple.devicecheck.error error 0 Did you manage to find more information about this error code ? Thanks.