title: pgadmin-4 in docker failed with gunicorn server start error
body: <p>I am trying to run pgadmin in docker like below and getting exception while starting gunicorn 20.0.4 error. Any pointers to fix this?</p>
  <pre><code>docker run -p 80:80  -e &quot;PGADMIN_DEFAULT_EMAIL=email@domain.com&quot; -e &quot;PGADMIN_DEFAULT_PASSWORD=postgres&quot; -d dpage/pgadmin4
  </code></pre>
  <p>Docker logs</p>
  <pre><code>NOTE: Configuring authentication for SERVER mode.
  [2021-08-13 03:03:04 +0000] [1] [INFO] Starting gunicorn 20.0.4
  [2021-08-13 03:03:04 +0000] [1] [ERROR] Retrying in 1 second.
  [2021-08-13 03:03:05 +0000] [1] [ERROR] Retrying in 1 second.
  [2021-08-13 03:03:06 +0000] [1] [ERROR] Retrying in 1 second.
  [2021-08-13 03:03:07 +0000] [1] [ERROR] Retrying in 1 second.
  [2021-08-13 03:03:08 +0000] [1] [ERROR] Retrying in 1 second.
  [2021-08-13 03:03:09 +0000] [1] [ERROR] Can't connect to ('::', 80)
  </code></pre>