Please ensure that your device is securely connected and that the charger is plugged in to the wall. Some wall outlets can be loose. While connected to the device jiggle the charger at the wall outlet. If the battery icon flashes try using a different outlet.
Please check the wire for any cuts or breaks. Please ensure that the USB plug fits securely into the charger, and the micro-USB plug fits securely into the device you want to charge.