Firstly, 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.
Secondly, if the issue cannot be resolved, please check the software version of the TV and call the TCL hotline for further help.
The software version could be checked on the TV: Settings-->Device Preferences-->About-->Product Information.
Note: On some TCL TVs, the Product Information is Contact Us.
