UN55KU600DFXZA and UN65KS800DFXZA neither will stay connected to wifi, while everything else in the house does.
Have to constantly disconnect from power and reconnect, it is the only way.
I've had success with the hold down the power button, and disconnecting from the network and then setting it up again would sometimes buy me a day or two. I would try manually inputing your DNS from your wireless router into the settings on your tv. People have also had success with google's 22.214.171.124 or 126.96.36.199. I got tired of resetting every night, still had the issues regardless of DNS settings, and Samsung was no help. I got a wifi extender and use that to make a wired connection. If your TV is mounted, that is probably not a very reasonalbe option for you.
I have no idea what the issue is, but this board is littered with similar complaints and smart TV that can't connect to the interenet is pretty pointless.
Under your network settings on your TV change your DNS address from obtain automatically to 188.8.131.52 or look on your wifi router your and it will have your ISP address you can try that as well. Some people have had success with these manually entered options.
Whats the model of your TV userEZ01DEyj2Z? Have you tried the DNS change as outlined above?