code: public synchronized void connectionFailed (Connection conn, IOException fault)
      {
          // remove the session from the connection map
          PresentsSession session = _conmap.remove(conn);
          if (session != null) {
              log.info("Unmapped failed session", "session", session, "conn", conn, "fault", fault);
              // let the session know the connection went away
              session.wasUnmapped();
              // and let the session know things went haywire
              session.connectionFailed(fault);
  
          } else if (!(conn instanceof AuthingConnection)) {
              log.info("Unmapped connection failed?", "conn", conn, "fault", fault, new Exception());
          }
      }
docs: Called by the connection manager to let us know when a connection has failed.