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I transferred data from iPhone 8 to iPhone 12 mini, using the iTunes Backup / Device to device migration. I wasn't getting push notifications for one app that I was already installed on my old iPhone. I checked the push notification settings for that app, and everything is enabled as before. I toggled the settings to on/off but it did not help. I tried to log out and log back in to that app, but that also did not fix the issue. Then I deleted and reinstalled the app, and then at the time of login, the app asked me whether I want to allow push notifications. I clicked Allow, and now notifications for that app have started working. Is it common behaviour? If not how to handle this?

We are using apple's device check api to prevent fraud happening for our app. As per tutorial, on client we added code to get ephemeral token and converted it to base64 string to send it to our server. Now when our backend queries the state of the device with Apple with fresh ephemeral token from device we get response as 'Missing or incorrectly formatted device token payload'.Can you please let us know what wrong we are doing? Also please let me know if you need any information.