If the wrist stops operating properly and displays a communication error, there is one most likely cause.
The wrist has disconnected during use. Check the USB cable connection to the CPU and restart the system. If the error persists, proceed to check the USB connection to the wrist board (located inside the tower on the lower left of the back wall). If connected, the red LED on the board will be lit. Restart the system.
For E13 wrist error: Follow these steps