ROES Server - Error EnsembleCommunicator

A newly installed ROES Server v3 can show this error over and over in the Messages pane/log:

EnsembleCommunicator(doHeartbeat) – Communication Error: For input string: “”

If you are running a single server environment: Stop everything (printers and server) click the cog at upper right to go to Settings.  In the upper left quadrant check the box to Run isolated and click the nearby Apply button in the same area.  Then click the Back button at upper left to return to the main panes.