@OJSS 

Does your password have special characters? Try changing the password to something simpler to test.

Another thing you can try is to keep the password and change the network name.

If other devices can connect to Wi-Fi properly, this might mean something wrong with your smart TV. Faced with this, you can try to force restart your TV, reset the network setting on your TV, check the software update. By the way, if what you are using is Apple TV, using Joyoshare Apple TV repair tool can get your TV back to normal without any data loss.