DIAGNOSIS The continuous alarm indicates a high internal temperature, typically from a first-time power-on or a door left ajar. The unit is alerting you it cannot reach its set point.
FIX First, ensure the door is fully closed and the magnetic seal is engaged. Second, if this is the initial startup, allow 24 hours for the interior to stabilize at the set temperature. The alarm should auto-cancel once the target temp is reached. Do not adjust the thermostat during this period.
IF THAT DIDN'T WORK Manually reset the control board. Unplug the unit from the wall for 5 full minutes. This clears any error state. Plug it back in and set the thermostat to 40°F. Monitor for 2 hours.
HEADS UP The alarm sensor is located on the rear wall. Do not block it with tall bottles or cans. Persistent alarm after 24 hours of runtime suggests a compressor or refrigerant issue requiring service.