@dnka What is the led status of the third Deco? Please ensure that it is pulsing blue. You can hold the reset hole for 1s to reset it. And you can connect the third Deco to the main Deco by wired...

@Billy01 Hi, you can open the port for the device which has NAT strict type via port forwarding /virtual server feature to solve your issue. May it help.

@PabloH Please give us some websites that cannot be loaded. Can you access internet with the Xiaomi cellphone? Try to change the DNS server of Deco E4 to give it a go....

@waynegr Hi, please try to clear the browser cache and enable the antivirus feature, then please access these websites and verify whether it can be blocked. You can add the domain name of the website...

@KeefyC The feature to turn on/off 2.4GHz/5GHz will be added via the firmware upgrading. It is hard to evaluate which wifi band you have connected considering they use the same SSID, but there are...

@Coll Glad to hear that it works. With Deco M4 works with a pure modem, to make internet work, we need to configure the Deco M4 as the main router with the parameters given by ISP. Best regards.