My ISP Modem is still working, but my Deco is still showing red dot and on the app it also says no internet connection. I have tried unplugging and plugging in the ethernet cable multiple times but it's no use. 

I have also rebooted the Deco unit both through the app and also manually switching it off and on again. 
I have also tried resetthing the Deco unit and connecting it again, but it's still the same. Still showing no internet connection.