Is the controller charging properly? You can check the controller's battery level by opening Controllers on the HOME Menu.If you start charging the controller while this screen is open, a charging symbol (x) will be displayed.
Is the controller charging in a place that is too hot or too cold? Please charge controllers in a place where the temperature is between 5 and 35°C.
Has it been a long time since the controller was charged? The controller's battery can be drained even when you're not using it. If too much time passes, the controller may become unable to charge. Please charge controllers at least once every six months.
Have you been repeatedly charging the controller? The controller's battery life will gradually be reduced with repeated charging. When the battery life becomes extremely short, even if the controller still charges correctly, it's a sign that the battery needs to be changed.
If this happens to a Joy-Con controller or Nintendo Switch Pro Controller, please contact Nintendo Customer Service so that they can check the batteries.