Lint screens lie. A thin film of fabric softener on the mesh passes a glance and still chokes airflow. Wash the screen with soap and water, then look at the duct.
Unplug the dryer. Pull the duct off the back. Plug the dryer in, set a timed cycle, and dry one damp towel with a window open. Stay in the room. If that towel dries in the normal time, the heater and the drum are fine and the duct, the elbow, or the outside hood is the restriction. A vinyl duct that was shoved back against the wall with a kink will fail this test every time. So will a bird screen packed solid, and a hood flap painted shut.
Restricted airflow overheats the heater box. On many electric dryers the thermal fuse then opens and stays open. After that the drum turns, the timer runs, and there is no heat at all. People replace the heating element. The element is often intact. The fuse opened because of the vent, and a new element will fail the same way if the duct stays clogged.
Gas dryers add a smell check. A weak igniter gives you a tumble and no flame. A smell of gas with the dryer switched off is not an igniter problem. Leave and call the gas utility.
More laundry symptoms are on the washer and dryer page.