Why is my iPhone 6 showing those gray lines?

So i bought an iPhone 6 and when i try turning it on it is showing the apple logo for 1 second and than instantly gets black. If i turn it on and hold the power button it shows the apple logo for 3 seconds

And now, i did hold home button and power button it showed the apple logo for like3 seconds and than it showed those gray vertical lines see the picture

Anyone knows what that could be?

here is the picture with the gray lines

Update

Tried the screen on another iPhone 6 it is also showing gray lines see picture