Sense 2 screen is black and can't sync

[Camillehgv]

My sense 2 was turned off for few months, now when in charge, screen is showing Fitbit logo and a Red Cross. 
when trying to synch with my phone , Bluetooth seems working as the app is asking me for the 4 numbers that should be shown on my watch, but the screen is of my watch is black and I can’t synch it

Moderator Edit: Clarified subject

[ManuFitbit]

It's good to see you participating in the community @Camillehgv.

Thank you for providing the details about this situation with your Sense 2. Sorry to know that you are having difficulties.

I don’t know how long you put the device in the charger. Please make sure the device has enough charge and try again. Because the device was off for many days, you may need more time on the charger.

If you feel like the device is not charging correctly, please see the following articles: Why isn't my Fitbit device's battery charging?

Sometimes the charging contacts may need some cleaning: How do I clean my Fitbit device?