Our app server is having some TLS related issue with the new iOS 26 (It works with iOS 18 and below). When opening the domain url in iPhone Safari browser with iOS 26, it showing the error as below: We followed the instructions from this link (https://support.apple.com/en-sg/122756), to run the following command: nscurl --tls-diagnostics https://test.example in Terminal app. It shows TLS failed with error: -9808 Could anyone please help explain what exactly the issue is with our server certificate, and how we should fix it? Thanks so much!

We integrated DeviceCheck framework into our app to prevent fraudulent call to our app service around one year ago. Recently, we received a few cases related to this function over Christmas Eve period. Based on the logs we have, it indicated both the following two functions returned errors. But we don't have the exactly errors logged and now we cannot replicate. DCAppAttestService.shared.attestKey() DCAppAttestService.shared.generateAssertion() The other finding we have is some users reporting this issue recently upgraded their devices from iOS 18 to iOS 26. So we are suspecting it's due to either the OS upgrading, or Apple's app attest service degrading. Anyone encountered the similar issues before, or have any idea regarding the root cause? Thanks!