It can be a network issue or loading issue. JTS use the Discovery URL of each registered application to retrieve the application information. If for some reason (network congestion, or the MN_Server being overloaded) JTS cannot get the response within a reasonable time period, it will just show "Unknown". The problem should be recorded in the jts.log file, check it for details. I don't think you need to re-run /jts/setup at all.