Get out your manual and go through the specific steps, most of the time it seems that I have had to go through the whole process twice -- and I have connected dozens of Samsung Smart TVs, yet I have no idea why the second connect attempt is seemingly always needed.
Insure that your gateway address is assigning an IP address if you use the auto setting, otherwise set a static address in the gateway network range.
Also, insure that the network range is one that is compatible with your TV.
Are you connection wired or wireless? If wireless, insure that your router broadcasts its SSID and that you enter the correct wireless security passkey into the TV.