Fanuc Alarm 401 (SERVO ALARM: n-axis VRDY OFF) — this is a standard Fanuc alarm, meaning the "ready" signal from the servo amplifier isn't reaching the CNC. Check the following: Step Cause/Check 1 Check the screen to see which axis is throwing the alarm (X/Y/Z/Spindle) 2 Check if the servo amp (drive) itself is showing an alarm (check the drive's display/LED) 3 Verify main power supply and control power (200V/24V) are correct 4 Confirm the emergency stop circuit is properly released 5 Check the connection cable from servo amp to CNC (JX1/JX2 or COP10A/B fiber optic) for looseness/damage 6 Check if the motor has overheated or is overloaded 7 Check if a breaker has tripped (on the servo amp power supply unit) Quick fix: First, reset the amp and power-cycle the machine (off/on). If it recurs, note the servo amp's own alarm code (shown on the drive's display) — that will help pinpoint the exact cause.