Szymon_Orthodox Don’t worry! It could be a software certification issue, which may happen after major updates.
I guess that Google may flag the device as “modified” or something.
You could try the following things in order, instead:
- Update Google Play Services and Play Store: Open Play Store, update everything and restart the phone;
- Check for Google Play System Updates: [Settings > Security & Privacy] > Updates] Install any Play System update, if any;
- Clear cache of these apps: Google Play Services and Google Play Store;
- Just wait a day or so. If you updated anything, Google will revalidate the device integrity.
Let me know if any of these worked instead!