If the TV cannot connect to the 2.4GHz band wifi network successfully, please follow the below methods to do the troubleshooting:
1. Check whether the TV could connect to the 5GHz band wifi network from the same wireless router. In addition, please confirm whether your mobile phone can connect to this WiFi.
2. Please ensure that there are no special characters in the SSID and the wifi password, such as *&^%$#.
3. Please check the Time and Date on the TV. If it is incorrect, please try to correct it.
4. Try to restore the TV back to the factory settings: press the Home button and select Settings Device Preferences Factory Reset.
If the issue cannot be resolved, please feel free to call the TCL hotline for further help.