1) The wrong end of the tracker body has been inserted into the USB charger and
2) The gold coloured charging strips on the tracker are not facing the charging contacts inside the USB charger.
If the battery of your fitness tracker has been completely drained and left unused for an extended period, it may take some time for it to engage and start charging.
You can try pressing and holding the control button for a few seconds to initiate the charging process and leave the device connected to the charger for a while.
You can also try charging your fitness tracker with a different USB charger or USB port on your computer. In most cases, allowing the fitness tracker to charge uninterrupted for a while should help it regain enough power to turn on.