Docker eeacms/varnish: Got unexpected response code from Varnish: 500

[boesbo]

When I try to save the configurations I have these errors:

Error determining Varnish version: Got unexpected response code from Varnish: 500
Failed to apply the VCL to varnish:6082: Failed to load configurator
Error determining Varnish version: Got unexpected response code from Varnish: 500
Failed to load configurator

The configurations are these:

Varnish Version: auto
Server List: varnish:6082
Varnish Authentication Key: (empty)
Config File Location: {{root_dir}}/var/varnish/default.vcl
Custom VCL File - Top: (empty)
Custom VCL File - Bottom: (empty)
Custom VCL Template: (empty)

Docker-compose:

...
  varnish:
    image: eeacms/varnish:4.1-6.2
    depends_on:
    - nginx
    environment:
      BACKENDS: "nginx"
      BACKENDS_PORT: 80
      ADDRESS_PORT: ":6081"
      ADMIN_PORT: ":6082"
      DNS_ENABLED: "true"
      PARAM_VALUE: "-p feature=+esi_ignore_other_elements"
    networks:
    - magento-network
    labels:
    - traefik.backend=varnish
    - traefik.port=6081
    - traefik.frontend.rule=Host:local.test.com
...