Smart home problems by symptom
Start from what the device is doing (or not doing). Every guide starts with the free checks in the app and web interface.
Offline & Wi-Fi
Firmware update
- ShellyShelly BLU device unresponsive after a failed update: rescue via bootloader modeIf a BLU device's firmware update aborts, the official documentation says it stays in bootloader mode. The update can be repeated from there: forget the device in your phone's Bluetooth settings, reinsert the battery, select it in the Shelly Debug app within about 40 seconds and start a slow OTA update. Shelly recommends an Android phone for this.Battery-powered BLU devices, e.g. BLU TRV, BLU Button, BLU H&T, BLU Door/Window, BLU Motion ·
- ShellyShelly firmware update fails or is stuck at 99% (Gen3/Gen4): what helps and what doesn'tThe update aborts, reports an error or stays at 99%. First reboot and start the update from the local web interface instead of the app, check the Wi-Fi signal, briefly turn off Eco mode and update devices one at a time. Never cut power during an update. If that doesn't help, Shelly support is the right contact for Gen2+; according to the sources a factory reset does not fix it.Gen3 and Gen4 devices (e.g. Plug S Gen3, Plug M Gen3, Pro 3EM, 2PM Gen4); much of it also applies to Gen2/Plus ·
Cloud & app
- ShellyShelly: "Device belongs to another user" – check the device ID and fix it properlyThe Shelly Cloud assigns each device to exactly one account. A factory reset doesn't remove that. First read the device ID: if it's only 6 characters, Shelly support says to use the long ID (longifyid) or update the firmware. With 12 characters, the previous owner has to remove the device from their account; otherwise Shelly support helps with the device ID and proof of purchase.All Shelly devices with cloud connection (Gen1 to Gen4), common with second-hand devices ·
- ShellyShelly keeps going offline or won't connect to Wi-Fi (incl. FRITZ!Box): settings that actually helpShelly devices need a stable 2.4 GHz Wi-Fi: 20 MHz channel width, channel 1, 6 or 11, WPA2 (AES), no band steering and enough signal. On a FRITZ!Box that means: fix the channel, WPA2 instead of mandatory WPA3, check PMF and let devices talk to each other. Only then network reset and re-adding.Gen2/Plus, Gen3 and Gen4 (Wi-Fi devices); the principles also apply to Gen1 ·