By restarting your device, you will kill all the processes running in the background as well as the one which might have prevented you from connecting to Wi-Fi network(s). Also, you will reset the Wi-Fi card (or adapter), which might have failed to load properly.
Maybe the real reason for this issue is that you are trying to connect to another Wi-Fi network which has a similar SSID (name) as your own. Double-check the SSID of your Wi-Fi network and compare it with the one you see on your device and make sure that they are identical.
Some Smart TVs have an inbuilt Wi-Fi module, whereas others need a Wi-Fi dongle which is sold separately. If your TV needs a USB Wi-Fi module to connect to the Internet, make sure to insert it in the TV.
You can enable the Wi-Fi module in Settings -> Network (depending on the brand).
If you don’t receive the email in the next 2 minutes please check your junk folder, and add [email protected] to your safe sender list.