Kenmore Rotary Control Knob Does not stay at 'ON' position

I have Kenmore dryer 970-C80032-00. When I turn it's rotary knob to "ON" position , it does not stay in the that position and goes back to the off position immediately and thus the dryer cannot start ?

What could be the possible reason for it ?

Can no power in the socket be one possible reason for it ? though I suspect as even if there is no power the switch should stay there in "ON" position