No log in Orchestrator for a robot (Orchestrator 19.10 on premise)

Currently I found issue “No log in Orchestrator for a robot”, I got same error message
Error while closing the websocket: System.Net.WebSockets.WebSocketException (0x80004005)
Like this case: No log in Orchestrator for a robot and Solution from this case is No log in Orchestrator for a robot

However, we need​ to​ know​ about the​ root cause and how to prevent this in the future.
Could someone help to suggest me, please?