Same problem here about 5 months in on a new 58 inch. Connects to router but fails to connect to internet. Was playing around with my BT home hub settings then it suddenly connected again but the next day its gone again so think that was just luck initially. Will be using the Richer Sounds warranty for repair or replacement. Note I have 2 Samsung smart tv's and only this latest one is affected.
Update on a quick fix.. if you go onto your router (I have BT Hub), settings, refresh wireless channel, smart wireless and hit refresh. Wait a min or 2 and try the TV again it miraculously connects!
This router refresh re-connects on another channel so poss it's something to do with channel interference. Still clearly an underlying fault with the TV but this should work as a quick fix for anyone having the same issue.
I'm going to recheck the channels it's trying to hit when it next fails. I have a feeling it's randomly connecting to the 5GHz channel on the router instead of 2.4GHz which the TV is set to use.
I was unable to connect to the internet on my series 6 50" curved TV. I read all the comments and considered following each one. Then I remembered that I had updated the software on the TV and shortly afterwards the TV could no longer reconnected. I disconnected the power source for 5 minutes and then rebooted. The broadband options came up and I reconnected. It worked.
After hours of trying to make the Samsung smart tv work with the AT&T modem/router along with my own router and trying various tricks, such as changing the DNS to 184.108.40.206, I found one solution that worked for me. Disabling packet filtering on my AT&T modem/router and restarting modem and my router fixed the issue