If the TV displays an error message, this will provide a lot of helpful information.
If it detects that the password for the network is incorrect, you should make sure that you are inputting the correct password. If you aren't sure what your password is, contact the person who helped you set up your network. Sometimes the password is printed on the bottom of your router.
If the MAC address has failed, you need to perform a factory reset on your TV. Navigate to Settings > Support > Self Diagnosis > Reset. Then enter your PIN (0000 unless you changed it). After the reset is complete, try the network test again. If the Mac address fails a second time, your TV requires service.
If you do not see an error message, continue troubleshooting.
Power-cycle your network.
Unplug your router, modem, or both, and your TV.
Wait 2 minutes.
Plug in your modem and wait for all the lights to come on. Do the same for your router (if you have both).
Plug in your TV.
Try the network connection again. If it fails, look at the image to see if it is still not connecting to the home network, or if it is not connecting to the internet. Also, check if an error message is displayed.
If it still won't connect to the home network, continue troubleshooting.
Update the Software on your TV.
Navigate to Settings > Support.
Hover over Software Update to view the current software version on your TV. It is listed to the right.
Visit Samsung's Download Center to obtain the software file for your TV.
If the software version on the website is higher than the version on your TV, download it.
Once the file is downloaded, extract the file to the root of a USB thumb drive.
Insert the thumb drive into a USB port on your TV.
Navigate to Settings > Support > Software Update > Update Now.
After the update is complete, try the network connection again. If the network connection fails to the home network, continue troubleshooting.
Reset the TV.
Navigate to Settings > Support > Self Diagnosis > Reset.
Enter the PIN for your TV (0000 unless you changed it).
After the reset is complete, try the network connection again. If the TV fails to connect to the home network, contact your router manufacturer to see if there are any firmware updates