If you have a technical problem with a Sonoff device purchased from us, please first read the technical knowledge base below to find the solution to your problem. Approximately 95% of problems can be resolved with the troubleshooting guide below.

Sonoff WIFI device pairing problems

If you have a technical problem with a Sonoff device purchased from us, please first read the knowledge base below. Approximately 95% of problems can be resolved by following this troubleshooting guide.

Sonoff device pairing problems

1. Did you enter your WiFi password correctly? Seems trivial, but it's the most common cause. Watch out for capital and special characters.

2. Check the WiFi band: 2.4 GHz vs 5 GHz Sonoff devices are only compatible with 2.4 GHz WiFi networks. They cannot connect to the 5 GHz channels offered by modern routers under the same name (SSID).

  • Why 2.4 GHz? This frequency has a higher penetration power through walls and floors, giving you wider coverage, ideal for smart devices distributed throughout your home.

  • Solution: If your router is "Dual-Band" and broadcasts both frequencies under the same name, try temporarily disabling the 5 GHz band in your router's settings during the pairing process. Alternatively, rename the 5 GHz network (e.g. "WiFi_Home_5G") to separate them.

3. How many devices does your router support? Standard routers (offered by internet providers) can support a limited number of simultaneous clients (often 15-20). If you already have a lot of phones, laptops and TVs connected, your router may refuse to connect your new Sonoff device.

  • Tip: For a stable smart home, we recommend upgrading to a WiFi 6 (802.11ax) or Mesh router, which can handle over 50-100 devices simultaneously.

The eWeLink app cannot find the device

If the scan process fails, check the following:

  • Mobile Data: Disable mobile data (4G/5G) on the phone during pairing. Sometimes the phone tries to send data over the mobile network instead of WiFi, blocking communication with the Sonoff device.

  • Bluetooth and Location Permissions: New versions of Sonoff use Bluetooth for "Quick Pairing". Make sure Bluetooth and Location (GPS) are enabled on your phone and that the eWeLink app has permission to use them.

  • AP Isolation: Check your router's settings to make sure that "AP Isolation" or "Guest Network" is not enabled. This prevents devices on the same network from communicating with each other, so your phone will not be able to "see" the Sonoff relay.

The device appears "Offline" periodically in the application

If the device has been configured but becomes unavailable:

  1. Weak WiFi signal: Check that you have sufficient signal where the Sonoff is installed. Thick walls or metal enclosures may shield the signal.

  2. Outdated Firmware: Go into your device settings in the eWeLink app (the three dots in the top right) and check for a red dot under "Firmware Version". Updates often fix stability issues.

  3. Power Supply: If you are using low voltage Sonoff modules (e.g. Sonoff RE5V1C or DC 7-32V models), make sure the power supply provides sufficient amperage (minimum 1A-2A). A poor power supply can cause WiFi chip restarts under load.

How do I reset a Sonoff device?

If nothing works, a hard reset is the best solution:

  • Most devices: long press the pairing button (approx. 5-7 seconds) until the LED starts flashing rapidly in a specific mode (e.g. two short and one long blinks).

  • Bulbs (Slampher/B02/B05): Switch the bulb on and off 3 or 5 times consecutively from the wall switch until the bulb starts pulsing.

  • Touch Switches (TX Series): Long press any of the touch buttons until you hear a beep or the LED flashes rapidly.

Issues specific to Sonoff Zigbee devices

Unlike WiFi devices, Zigbee devices (such as SNZB sensors) require a Zigbee Bridge (Sonoff ZBBridge, iHost, or Dongle Plus) to work in eWeLink.

  • Bridge Distance: Zigbee devices operate in a mesh network. If a battery sensor is too far away, it will appear offline. Tip: Add a plug-in powered Zigbee device (e.g. Sonoff ZBMINI) between the sensor and the Bridge to act as a signal repeater.

  • WiFi interference: Zigbee uses the same 2.4 GHz frequency. If you experience frequent disconnects, change the router's WiFi channel to channels 1, 6 or 11 to leave room for Zigbee frequencies.

  • Low battery: Zigbee sensors are sensitive to voltage drops. If a sensor refuses to reconnect, the first solution is to replace the battery (CR2032/CR2450), even if it previously appeared "Ok" in the application.

  • Reset: To pair, press the "Reset" button with a paperclip for 5 seconds until the LED flashes red/blue.