Apple iPhone 12: Problems with contact tracing apps

The first buyers have already received theirs Apple iPhone 12 or 12 Pro. When importing a backup, some users noticed that contact tracing apps no longer work. All information.
In some regions, iPhone 12 buyers who use a contact tracing app due to COVID-19 have difficulties with it. When opening it, an error message appears indicating that the app cannot be used. This comes from importing an iCloud backup, as an important setting is not reactivated here. Since this does not happen when the backup is restored, it is not clear to most that this is necessary.
In order to avoid this error message, you have to press the button "Activate meeting messages" in the settings under "Meeting messages". Deleting the app should also work, but this is not recommended. This is because all recorded data is deleted, which would result in unsuccessful contact tracing.