Most often the problem is that the wireless router is too far away from the television. Moving the router closer to the TV will resolve this issue. The wireless router is the device that connects to the internet service in your home or office that makes possible the wireless internet connection to TVs, as well as laptops and smartpones.
The next most likely cause of a lost wifi connection is another wifi-enabled device that is physically close to the TV. Moving the device further away from the TV or disabling its wifi capability will remedy this situation.
A poor connection might also mean that either your network traffic is high or the network bandwidth is low. The bandwidth of your network should be greater than 5MBPS and you should limit any other bandwidth-hungry applications running on your wireless network.
Older TVs have the ability of connecting to the internet using a hard-wired Ethernet LAN connection.
If you are experiencing slow connection speeds with other devices on the network, you can try rebooting (i.e. turning off-and-on) your wireless router, modem, and/or your Wi-Fi media adapter. If your TV has an Ethernet LAN (wired) connection, try disconnecting and reconnecting the cable from the TV. Another thing you can try with your TV or Wi-Fi media adapter is to search for another (unsecure) wireless router in your area and try connecting to it. If you have a smart phone with built-in hotspot capability, you can try connecting to it. If none of these things work, it means you have a problem with either your router or your modem.
If you suspect that the problem is with the television, then it would be the main board that will need to be replaced (see Replacing Circuit Boards).
An internet connection for your television allows you to watch such things as Netflix, Hulu, Amazon Video and Sling Television. Many of today's TVs have built-in functionality for this. If your TV does not have this internal capability, but there is Wi-Fi capability in your area or you do have a wireless router, then you can purchase a device that connects to the TV that will provide an internet connection for your TV. These devices are known as a Wi-Fi dongles, wireless media adapters or serial Wi-Fi adapters.