Hi  @Tom-Jones,

May I know what is the model of your deco? Please take screenshots with error message. 

Are other clients working properly? If you Cannot access certain websites/apps when connected to Deco network, please try to disconnect the main Deco from the Modem and connect your PC directly into the Modem, verify if the PC could access the specific websites, it might be an ISP issue if your PC is not able to access the specific websites.