Why my thermostat keep disconnecting

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The app shows everything is fine but then the unit connected to the boiler show alarm, the warning light and WiFi keep blinking!

However if I make any changed in the app, let's say tune on one of the tado valves it just doesn't do anything, it shows it on the app with new changes but the change doesn't apply to the valve or the main unit.

The bridge is right next to the unit, I have a very stable Internet connection!