@siroscar 

Do you have any device connected to the C60 with an Ethernet cable? If so, do those lose connection as well?

When the issue happens do you notice a change in the LED lights pattern or color? Which ones?

@Tony I do not have a laptop or any other device connected by an Ethernet cable. Although I did take my router down from the wall and connect it briefly a few hours ago to my laptop via Ethernet. I didnot notice any loss then. 

The loss of signal is so quick that I can't always time correctly to glance at the router. However, I have seen the internet light turn from green to amber once in a while.

 

@siroscar *UPDATE*

I've restored to V3 of the firmware last night. The router seemed fine for a few hours. But when I woke up today I noticed most of my devices are not connected to the internet. It still tells me to sign in anymore on the phone, but the light does flicker from amber to green.

My only hope right now is to use OpenWrt firmware and switch one of the lan ports to a wan port and see if this solves the problem.

@siroscar 

Hi Siroscar, this seems exactly similar to my problem with the Archer C80. The symptoms are exactly the same as with the internet dropping in and out. The green light flickers to orange for me and sometimes after I've left a device idle, it will show the device isn't connected to the internet after picking it back up.

Here's a link to my thread with the C80:

https://community.tp-link.com/us/home/forum/topic/226700