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FANUC Alarm HOST-143 — WARN Comm port cannot be closed

FANUC HOST-143 (“WARN Comm port cannot be closed”): The selected hardware port defined for the Comm Tag could not be closed. First check: Power the controller OFF and then ON and try again.

Updated 2026-09-17 · LogrobotLM reference

Description

The selected hardware port defined for the Comm Tag could not be closed.

Remedy

Power the controller OFF and then ON and try again. If the error occurs again a cabling or hardware problem might exist with the port.

Related codes

HOST-141WARN Protocol Start/Stop errorHOST-142WARN Connection errorHOST-144WARN Comm Tag errorHOST-145WARN Permission denied

Indicative field information — the robot manufacturer's manual and safety procedures always prevail. Never bypass a safety device; apply lockout/tagout (LOTO) before any physical intervention. How this reference is built →