Troubleshooting offline sensors
A step-by-step checklist for a sensor that stopped reporting — power, range, connectivity, and gateways.
Updated August 20, 2026
Troubleshooting offline sensors
A device shows as offline when the platform has not heard from it for longer than expected. FreshControls raises an offline alarm for that device rather than letting it disappear quietly, and escalates it like any other alarm — so silence is something you get told about, not something you have to notice. Readings taken while a device is off the network are not recovered, so treat an offline device as a gap to close quickly. Work through these checks in order.
1. Confirm it is really offline
Open the device and check the last seen time. A single missed report during a long reporting interval is normal. Treat a device as offline only once it has clearly missed several expected check-ins.
2. Check power
- Battery sensors — replace the field-replaceable batteries and confirm the sensor powers up. A low battery is the single most common cause.
- Wired boards and gateways — confirm the power supply or PoE injector is live and the status light is on.
3. Check range and placement
- Wi-Fi sensors — a freezer's metal walls attenuate the signal. Confirm the sensor is within reach of an access point and that the network password has not changed.
- LoRa sensors — confirm a gateway is powered and within range. Thick walls, racking, and distance all cut range; moving a gateway closer often fixes a stubborn sensor.
4. Check the gateway
If several sensors went offline at once, suspect the gateway they share rather than the sensors themselves.
- Confirm the gateway is powered and its uplink light is healthy.
- For Ethernet gateways, check the network drop, the cable, and that the port is live.
- For cellular gateways, check signal strength; relocating the gateway or adding the external antenna option can help in a weak-signal spot.
5. Confirm it is back
Once a device is back on the network its next scheduled report clears the offline alarm and the history resumes. The period it was off the network stays visible as a gap in the record — that is deliberate: a compliance log should show what was actually measured, never a reconstruction.
Still offline?
If a device stays dark after power, range, and gateway checks, contact support with the device serial and we will help you narrow it down.
Related
Still need a hand?
If this didn't answer your question, our team is happy to help you get set up and running.
Contact support