This process will not delete any of your data, it helps when there is issue about the power:
1. Shut down your Mac.
2. On your built-in keyboard, press and hold all of these keys:
• Shift on the left side of your keyboard
• Control on the left side of your keyboard
• Option (Alt) on the left side of your keyboard
3. While holding all three keys, press and hold the power button as well.
4. Keep holding all four keys for 10 seconds.
5. Release all keys, then press the power button to turn on your Mac.
Reset the NVRAM:
Shut down your Mac,
then turn it on and immediately press and hold these four keys together:
Option, Command, P, and R.
You can release the keys after about 20 seconds,
during which your Mac might appear to restart.