Please provide more detail on this issue. What version of ThingWorx are you running? What are you attempting to connect to and what is expected in terms of the connection? Is it sitting idle much of the time?
It would also be helpful if you could provide the logs for a more in-depth review of the issue. Are you seeing errors from the other side?
Apparently, the platform is closing the WS endpoint because it did not receive any message from the edge within the "Idle Connection Timeout" (60 sec) period specified on the WSCommunicationsSubsystem.