1. Check if the internet connection on both devices (Smart TV and PC/laptop) are working and functioning.
2. If the internet connection is functioning, check if the devices are connected to the same WiFi network.
3. If yes, check the compatibility of the media file with your Smart TV by referring to your Smart TV's manual.
4. If the media file is compatible with your Smart TV, make sure that the required hardware is plugged in and connected correctly.
5. Else, activate the DLNA Media Server on your PC or laptop.
6. Try and connect your Smart TV to the DLNA Media Server.