External lockout can also mean that the limit switches are tripped, look for a these type switches around the burner and reset them by pressing the small button in the center of them, let me know. Then let me know what the furnace does from the time you turn it on until you get the lockout code,
Turned unit off then it restarted fine, until this morning now it starts to ignite then shuts down and the board show it still calling for heat.
Tried the reset on the limit switches and no luck. rechecked connections as well as the pressure switch.
Due to the lack of follow up. Due to multiple error codes I changed the board and now it is working correct.