The tado° app lists devices as offline when they experience a problem with connectivity. You can see if any of your tado° devices are offline by going into the tado° app and selecting Rooms & Devices.
However, tado° X devices store your heating schedules locally, so they will continue to follow your Smart Schedule even if the network connection is lost.
Note that if the Zone Controller device is offline, you could experience interruptions in heating from the other devices that rely on that device. Your devices should follow their preset Smart Schedules even without a connection, and you can always control your heating manually on your devices.
First, check that your tado° Bridge X (or other Thread border router) is powered and connected, since this is the central hub for your devices. If your Bridge X (or other Thread border router) is unplugged, offline, or too far away from your other tado° X devices, they will not be able to connect.
If your Bridge X is offline, refer to this article for troubleshooting.
If your Heat Pump Optimizer X (which can also act as a Thread border router) is offline, refer to this article.
If you have already successfully connected and controlled your devices via the tado° app, you can try to reconnect them by following these steps:
Check your internet connection. To do this, make sure you can connect to your home Wi-Fi network on your smartphone. If it is not working, please check that your router is powered. Try restarting the router. This will usually resolve a temporary issue with the internet connection.
Make sure that your Bridge X (or other Thread border router) is plugged in, powered, and has a strong signal. You can confirm signal strength by checking the LEDs on the front of the device.
Try adjusting the location of your Bridge X.
A central location is best. Plug your Bridge X into a socket that is an equal distance from all your tado° devices.
Make sure there are no large metal objects or devices that use radio frequency between the tado° devices and the Bridge X. If you can't change the location of these items, you can try adding another Bridge X to improve the rangeof your Thread network.
Check the battery charge level and recharge/replace if necessary. The devices will go offline if the batteries are completely depleted. If this doesn’t solve the problem, go to Settings > Rooms & Devices in your app to find out which device is offline. Restart this device. Please note: if the Zone Controller device is offline, all devices that belong to the same Heating Zone will be offline too. You can save time by restarting the Zone Controller first.
If your home is very large (especially with multiple levels) or you have more than 20 connected devices, you may need another Bridge X to extend the network to all areas of your home.