Breckwell stove starts fine. But shuts down. #2 light. Soot on glass.

Have a Breckwell p2000i. Been having intermittent problems with stove shutting down and number 2 light flashing. Tried all the easy accessible troubleshooting, such as cleaning out combustion changers, which did the trick previously. But not this time. Have not pulled the insert to get at the innards to check on tubes, blowers, etc. but before I do that I'm wondering if it's the door gasket. When the stove starts up and shuts down, clean glass gets immediately blackened with a fine layer of soot. Did the close the door on the paperthing in a couple of places and it pulls out fairly easily, not tearing like the paper I saw in a youtube video. If there isn't a good seal will that account for the quick shooting/blackening of glass?

I like to try simpler solutions first. I had an auger jam that I dealt with by poking at it to dislodge debris from the hopped above and below up through the chute that feeds the pellets --rather than by pulling the insert and dismantling the auger motor and taking out the auger.

Re the current problem, I found another thread here where the poster solved the #2 light problem by pushing the damper all the way in. Tried it, and the stove has been going for about an hour. I consider this a workaround not a solution but any ideas about what it could mean to avoid a #2 shutdown only if the damper is all the way in?