Hi Quinn, thanks for the swift response! I am targeting the iOS platform.

I received this same email after uploading an .ipa file to App Store Connect through the Transporter app. The following is where I went wrong: I distributed the app using ad hoc. The following steps are the solution for my error: Archive app Distribute on TestFlight and the App Store Export Open ExportOptions.plist in the newly created folder from the export. Make sure the method property has the value app-store if you are uploading to App Store Connect/TestFlight like me. Drag and drop the exported .ipa file to Transporter. Deliver your app to upload it. And that's it!

Hi Quinn, I needed to import it into our iOS app because, previously, I was asked to handle the authentication and token refresh on the frontend side. So that it was led me to this path. However, by going through the Sign in with Apple steps again, I came to realize that there's no need for me to do the token refresh. I can just check the user's credentials upon app launch. I still followed through getting the raw key bytes using an online tool (ASN.1 JavaScript decoder), but I was still unable to make it work. I believe I'm doing something wrong along the way but I just don't know which one. Anyway, thanks a lot Quinn! Maybe I'll come back to this thread if I come across PKCS#8-related security topic again.

I use both Xcode 13.1 and Xcode 13.2 beta, but I still see the same error when building the project.