Touch screen problem

[Khayyam]

 I can not pull down the taskbar section at the top of the screen. It is insensitive to the touch of a 3 mm section of paint from the top of the screen. I do not know how it came to this situation, there is no physical deformation on the screen due to impact. I set the device to software factory settings, but it has not improved. Sometimes it heals itself spontaneously  What can be done?the same problem in diagnostics 

[MarlonUk1]

this seems to be a hardware problem, better to have it checked at your local service center Local support

[Khayyam · Accepted solution]

after downgrading my software from andriod n to andriod 6.0 marshmellow i can get rid from this problem

[Khayyam]

for your kind information its not a hardware issue