If the wifi network is unstable on the TV, please follow the below methods to do the troubleshooting:

1. Check whether the wifi network is stable on your mobile phone. If the wifi network is unstable on your mobile phone, please try to check the wifi settings on the wireless router. Usually, you could try to fix the wifi channel on your router.

2. Check the wifi signal strength on the TV. If the wifi signal is weak, the wifi connection will be unstable. Please try to put the TV nearer to the wireless router.
   

3. Check if there is wifi signal interference around the TV. Theoretically, the microwave oven and the Bluetooth devices will affect the wifi signal.
   

4. Try to restore the TV back to the factory settings: press the Home  button on the TV remote. Then select Settings-->Device Preferences-->Factory Reset.
   

5. If the TV has internet access, please check if there is a new version of software updated online or not.
   Press the Home  button on the TV remote, and select Settings-->Device Preferences-->About-->System update-->Network Update:
   
   

If the issue cannot be resolved, please feel free to call the TCL hotline for further help.