its a safety device that is trippiing because something is unsafe and is supposed to shut off. like high carbon monxide level due to invcomplete combustion
it may be trying to tell you something by shutting off....like "i am defective, dont try to relight me untill i am serviced by a professional"
if you feel sleepy, get fresh air right away and call fire dept!
is trying to tell you its not working correctly, pay attention, get steve away from the thing