Sense 2 stopped working

[Jeksmjek]

My sense 2 stopped working. I charge it and I only see the logo. It constantly vibrates for a fraction of second every 5 seconds. 
it doesn’t sync and on the app it shows that it does not exist 

Moderator edit: clarified subject.

[ManuFitbit]

Hi @Jeksmjek. Welcome to the community forums. 

Thank you for sharing the inquiry regarding the situation with your Sense 2. Sorry to know the inconvenience. Thank you for trying to fix it on your own.

I'd suggest following the steps below in the order listed:

• Unpair the Fitbit Sense from the phone's Bluetooth and also make sure it's no longer connect to the Fitbit app. 
• Force quit the Fitbit app.
• Turn off the Bluetooth.
• Shut off the phone and turn it on after 1-2 minutes.
• Turn on the Bluetooth.
• Set up the Fitbit Sense again.
• If there is no connection, restart the Fitbit Sense.

If you can't get started with the Fitbit Sense, usually a missing requirement is the cause. Carefully review the requirements provided in the help article Why can't I set up my Fitbit device? 

[Jeksmjek]

It doesn’t get detected by my iPhone 

it keeps turning on and off every 2 seconds 

[Jrevlhs]

Try holding down two buttons at once for ten seconds

mine turned off today while working out and it was fully charged and it wouldn’t turn back on 

I’m not sure how 

but anyway I saw someone say to hold a button down for ten seconds I tried them all alone and it didn’t work then I held two down for ten second and it turned on