I had to edit /lib/systemd/system/docker.service on my Ubuntu 16.04.2 LTS system to modify the line then and everything worked :-). The next step is to figure out how to protect the docker daemon form being hijacked.
https://github.com/techno-tim/techno-tim.github.io/tree/master/reference_files/traefik-portainer-ssl/traefik https://docs.technotim.live/posts/traefik-portainer-ssl/ https://www.grottedubarbu.fr/traefik-dns-challenge-ovh/
Conclusion When you are using NFS mount points with root account on client-side then export them with no_root_squash option. This will ensure you don’t face access related issues on NFS mount points