HA Restore via Container not possible / The onboarding page is always displayed

Hello everybody,
i want to move an HA Conainer to another server / docker-enviroment.

I do the follwing steps:

  1. Create a backup on source container (HA Settings > System > Backup) and download the backup file.
  2. Copy the backup file to the target system and decompress the file.
  3. Move the files from the data directory (backup file) to the new location of the new HA Container
  4. Set the persissions and owner of the files.
  5. Start the new HA container

… then i see the onboarding page of HA.

What could be the cause?
Have I forgotten something?