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FANUC Alarm BELL-121 — WARN Host name not recognized

FANUC BELL-121 (“WARN Host name not recognized”): Hostname currently setup on the controller for ethernet communications is not per convention for automatic Host Comm setup. First check: If standard BellTool Ethernet communications setup is desired, enter the correct 'Network Setup Number' at Setup screen at Controlled Start and press [F2] Setup to reconfigure.

Updated 2026-09-17 · LogrobotLM reference

Description

Hostname currently setup on the controller for ethernet communications is not per convention for automatic Host Comm setup.

Remedy

If standard BellTool Ethernet communications setup is desired, enter the correct 'Network Setup Number' at Setup screen at Controlled Start and press [F2] Setup to reconfigure. If you do NOT want Ethernet to be setup automatically, ignore this message and leave 'Network Setup Number' at 0.

Related codes

BELL-112WARN Minimum … positions to processBELL-120WARN I/O Hardware not installed

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 →