novncproxy in HA mode says Failed to connect to server (code: 1006)

Issue

• Horizon access times are slow.
• All attempts to access an instance console fail with the following Invalid Token error present in the logs :

Oct 23 16:49:19 osp1-controller03 nova-novncproxy: 11: 87.44.1.157: new handler Process
Oct 23 16:49:19 osp1-controller03 nova-novncproxy: 12: 87.44.1.157: new handler Process
Oct 23 16:49:19 osp1-controller03 nova-novncproxy: 13: 87.44.1.157: new handler Process
Oct 23 16:49:19 osp1-controller03 nova-novncproxy: 13: 87.44.1.157: Plain non-SSL (ws://) WebSocket connection
Oct 23 16:49:19 osp1-controller03 nova-novncproxy: 13: 87.44.1.157: Version hybi-13, base64: 'True'
Oct 23 16:49:19 osp1-controller03 nova-novncproxy: 13: 87.44.1.157: Path: '/websockify'
Oct 23 16:49:19 osp1-controller03 nova-novncproxy: 13: handler exception: Invalid Token
Oct 23 16:49:19 osp1-controller03 nova-novncproxy: 13: Traceback (most recent call last):
Oct 23 16:49:19 osp1-controller03 nova-novncproxy: File "/usr/lib/python2.7/site-packages/websockify/websocket.py", line 711, in top_new_client
Oct 23 16:49:19 osp1-controller03 nova-novncproxy: self.new_client()
Oct 23 16:49:19 osp1-controller03 nova-novncproxy: File "/usr/lib/python2.7/site-packages/nova/console/websocketproxy.py", line 56, in new_client
Oct 23 16:49:19 osp1-controller03 nova-novncproxy: raise Exception(_("Invalid Token"))
Oct 23 16:49:19 osp1-controller03 nova-novncproxy: Exception: Invalid Token