-If your Fitbit has been in storage for a while or just subjected to a lot of dust, dirt, or grime, the charging contacts on the underside of the device might be too dusty or dirty to charge, which in turn keeps it from turning on. You can clean it using the same techniques you’d use to clean an iPhone charging port. You can use a can of compressed air or a cotton swab to clean the area. You can even dab the swab (or a toothbrush) with a small amount of rubbing alcohol to clean the metal contacts.

-Your Fitbit might not be getting enough power to charge its battery. If possible, plug the Fitbit’s charger into an AC wall adapter rather than your computer. Any USB wall adapter will work. If you don’t have a wall adapter, make sure the charger is plugged into one of your computer’s primary USB ports (not a USB hub) and ensure the computer stays awake for several hours while the Fitbit tries to charge.

-Charge your Fitbit for a minimum of three hours. Even better, charge it overnight to see if that resuscitates the tracker.

-Restart your Fitbit. Like any piece of tech that is misbehaving, you may need to restart or “reboot” it. The exact process for restarting a Fitbit varies depending upon which model you own, but in almost every case it is as simple as plugging the tracker into the charger and then holding down the Fitbit’s main button for some period of time. To make sure you hold it down long enough to restart, hold it at least 20 seconds before releasing. If the restart is successful, you should see the Fitbit logo appear and the tracker will come to life.

1. Restart it multiple times, charging it in between each attempt. After you attempt to restart your Fitbit, if it is still not working properly, let it charge for several hours. If it’s still unable to turn on, restart it again. Repeat this several times, alternately restarting and charging it, until the Fitbit turns on normally. The philosophy behind this is that your Fitbit might need a minimum of one restart to just to get to a point where it can accept a charge, but it might not yet be recovered enough to turn on.
2. If you restart and charge your Fitbit three times and it does not respond, you can try the last resort: Reset the Fitbit back to its like-new factory conditions.