Batteries die. This causes most remote failures. Remove the back cover. Take out the old batteries. Insert two brand new AAA batteries. Check the positive and negative signs. Match them correctly.
Remotes hold residual charge. This freezes the circuit board. Remove the batteries. Press every button on the remote twice. Press and hold the power button for five seconds. Put the batteries back inside. Test the remote.
The TV often ignores the remote. This happens when the TV software crashes. Unplug the power cord from the wall. Find the physical power button on the TV. Press and hold it for thirty seconds. Plug the TV back in. Turn it on.
The remote uses an infrared sensor. Objects block this signal. Move books and decorations away from the TV. Wipe the front of the TV with a clean cloth. Dust blocks the sensor. Point the remote directly at the bottom right corner of the TV.
The IR emitter breaks over time. You need to check if it sends a signal. Grab your smartphone. Open the camera app. Point the top of the remote at your phone camera. Look at your phone screen. Press the power button on the remote. You see a purple or red light on your screen. The remote works. You see no light. You need a new remote.
You need to control your TV right now. Download the Vizio Mobile app on your phone. Connect your phone to the same WiFi network as your TV. Open the app. Follow the screen instructions to link your TV. Your phone is now your remote.
The remote is dead. You need a new one. Buy an official Vizio remote or a universal remote online.