I have evanell° heating products installed and my app shows that the Device Offline error. How can I fix this?

I have evanell° heating products installed and my app shows that the Device Offline error. How can I fix this?

Check evanell° server status
Device Offline is shown in the app when there is a problem with the connectivity of your evanell° thermostat devices.

If you are currently setting up your device, please make sure it is paired with the Gateway.

If you have previously paired and operated your evanell° devices, there are several other reasons why the app could now be showing Device Offliner error. Here are a few ways in which you can solve the problem:
1 Check if the internet connection is working. To do this, log in to your home’s Wi-Fi network on your smartphone. If it is not working, please check that your router is powered and reset the router. This will usually resolve a temporary issue with the internet connection.
2 If the internet connection is working, make sure that your evanell° Gateway is powered and connected to the router. Make sure that the Gateway is not positioned behind your router. If possible, use a longer Ethernet cable to move the Bridge further away from the router. Also make sure that no large metal objects or other devices that use radio frequency are placed between the evanell° devices and the Bridge.
3 If the Gateway is powered and is connected to the router, try moving and placing the Gateway in an upright position. This can help to improve the connection for your whole evanell° system.
4 Make sure that your Gateway is placed in a way that makes it equally far from all your evanell° devices. The distance between the Gateway and each device should be at least 3 meters. If the current position of your router does not allow for this, try using a powerline adapter to connect the Internet Bridge to the internet.
5 If the problem persists, check the LEDs on your Gateway to see if there is a problem.
6 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.
7 Also, check if the batteries of your devices are in a good state. If not, replace them.
If you can’t resolve your problem immediately or if there is no connection, you can always control your heating manually on your devices.