Error calling healthcheck: please enable `ping` to use health check

Traefik Traefik v2
,
16 
# grep ping docker-compose.override.yml
      - "--ping=true"
      test: ["CMD-SHELL","traefik healthcheck --ping"]
# docker exec -it traefik traefik healthcheck --ping
INFO[0000] Configuration loaded from flags.
OK: http://:8080/ping
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