My PS4 controllers stopped working

[Dr. Evil]

I was on Netflix when all of a sudden my PS4 controllers stopped working. It left this message:

"Cannot start the PS4. Connect the DUALSHOCK 4 using the USB cable, then press the PS Button"

It's in safe mode. How do I get my controllers to work again?

 

[Monsieur Xavier]

Have a look at these links and video, it might help.
NOTE : I will not be responsible for any data loss or hardware malfunction.

Consoles & Peripherals

Consoles & Peripherals

How to stop your PlayStation 4 from starting up in safe mode

Youtube tutorial :

Spoiler