Help My oneplus 3T has just crashed

[firedesire]

Tonight my phone just died ... it had plenty of charge and wasn't actually being used, just that when i did go to use it, it was dead.
I've tried the hold down volume/power buttons at the same time but with no joy, anyone have any tips ???

 

[Brush6136]

Tonight my phone just died ... it had plenty of charge and wasn't actually being used, just that when i did go to use it, it was dead.
I've tried the hold down volume/power buttons at the same time but with no joy, anyone have any tips ???

How long have you held the power button down for? I have had the odd experience where I've had to hold the button down for as much as 9 seconds instead of the usual 3.