Sometimes when the handle of the 3-point lock on my Pella door is turned into the lock position the shootbolt at the top does not go up all the way. Then the key will not lock the door. You can reproduce the problem with the door open, so I know it is not a problem of the shootbolt not fitting into the bottom or top plate. I have lubricated the place at the top of the door where the shootbolt pops up.
I have those exact same doors from Pella. They have been a problem for Pella. I posted a couple of years ago about what I found, Here is a link:
Pella Door won't lock (3 point lock)
A couple of pointers:
- Make sure the bottom part where the lower shootbolt fits into is very clean with no debris.
- If the door wasn't used much, you may have to take apart the entire assembly on the edge of the door and lube it up. Don't use WD-40, it doesn't last, since product recommendations are OT here, I won't go there, but there are great products out there, WD-40 just won't last.