Samsung Dryer Not Turning Off

Hello. My Samsung Dryer dv365etbgwr just keeps running. I have to keep the door opened all the time unless I’m drying clothes. If the door is shut, it just keeps on going. If I push the power button off and there is nothing on the display, it will still run with the door shut. There used to be heat, but now there is no heat and the timer doesn’t count down. Any ideas?