WebSocketSharp Error!An exception has occurred while receiving a message.

Hello
when i run unity example, i connect to my server, my server use Colyseus 0.9.24
but Unity get error "WebSocketSharp Error!An exception has occurred while receiving a message."
"WebSocketSharp Close!An exception has occurred while receiving a message.Code:1006"
what problem here?
Please help

I have the same question! Mine works 95% of the time but sometimes i get 1006 code, what does this mean?