Cable Internet Connection is Okay, but Wi-Fi is Down

I already experienced this situation twice, both on a router wherein all the cable and Wi-Fi connections are functioning.

Whenever it happens I can remotely connect to the device behind the router but no one will be able to connect to Wi-Fi and those already connected will not be able to browse the internet.

Computers who are connected to the router using cable (direct and indirect) will be able to browse the internet and the devices within the local network.

The only solution to this problem is to restart the router. Also, you can avoid this problem by minimizing the devices the connect through Wi-Fi.

But if it is the only Wi-Fi device in your network you need to buy an additional router to mitigate the problem.