title: Docker: error 500 - failed to start container
body: <p>I encounter this issue after running <code>java -jar shinyproxy-1.0.2.jar</code> and access my app:</p>
  
  <pre><code>Error
  Status code: 500
  Message: Failed to start container: Request error: POST http://localhost:2375/containers/create: 400, body: {“message”:“invalid reference format”}
  Stack Trace:
  eu.openanalytics.ShinyProxyException: Failed to start container: Request error: POST
  </code></pre>
  
  <p>From the help on shinyproxy.io: <a href="https://www.shinyproxy.io/troubleshooting/#failed-to-start-container" rel="nofollow noreferrer">https://www.shinyproxy.io/troubleshooting/#failed-to-start-container</a></p>
  
  <p>I have checked the firewall and it is disabled.</p>
  
  <p>I have also checked my docker.service file and everything seems in order:</p>
  
  <pre><code>[Unit]
  Description=Docker Application Container Engine
  Documentation=https://docs.docker.com
  After=network-online.target docker.socket firewalld.service
  Wants=network-online.target
  Requires=docker.socket
  [Service]
  Type=notify
  # the default is not to use systemd for cgroups because the delegate issues still
  # exists and systemd currently does not support the cgroup feature set required
  # for containers run by docker
  ExecStart=/usr/bin/dockerd -H fd:// -D -H tcp://127.0.0.1:2375
  ExecReload=/bin/kill -s HUP $MAINPID
  LimitNOFILE=1048576
  # Having non-zero Limit*s causes performance problems due to accounting overhead
  # in the kernel. We recommend using cgroups to do container-local accounting.
  LimitNPROC=infinity
  LimitCORE=infinity
  # Uncomment TasksMax if your systemd version supports it.
  # Only systemd 226 and above support this version.
  TasksMax=infinity
  TimeoutStartSec=0
  # set delegate yes so that systemd does not reset the cgroups of docker containers
  Delegate=yes
  # kill only the docker process, not all processes in the cgroup
  KillMode=process
  # restart the docker process if it exits prematurely
  Restart=on-failure
  StartLimitBurst=3
  StartLimitInterval=60s
  [Install]
  WantedBy=multi-user.target
  </code></pre>
  
  <p>I am using Ubuntu 16.04. Any help here?</p>