No lint collecting on lint screen:If no lint is present on the lint screen after a drying cycle, or if lint is on the wrong side of the screen, this problem might suggest that rather than gathering in the lint trap, the lint is backing into your dryer. The absence of lint signifies an obstructed clothes dryer vent.

Dryer Vent Cleaning Chicagoland Alets Resident To Act if They Find No Lint On Screen