@GodfreyGan The ISP is your internet service provider, the company to whom you pay for internet. Did they provide you a device for connecting online? if so what model is it? That device may already...

@bodjie7 CPE are generally Point to Point devices, namely 2 (or 3) CPEs transmitting over a large distance. Personally.. wouldn't have any more than a 1 : 6 ratio In AP mode... perhaps 12 / 15 would...

@Alex93 I would say this is expected behaviour if honest, what you have setup is 3x individual Access Points and not a "mesh" In a mesh setup the network will move the client from AP to AP as best...

@GodfreyGan Is your Main Deco connected to an ISP Router? If so don't set PPPoE.. leave it on Dynamic

@agustin85 Yes it is indeed I have seen users with 9x decos all connected. You can add the additional device from within the app

@ingeborgdot You wont need to configure anything on the other APs If you have the OC200 controller, which you said you did then configure the Wireless SSIDs and Passwords on there and get that setup....