Why does this say, "Unreachable Build"

[Uncrushed]

I've gotten that message before, but it was usually obvious why.  Here?  I'm not so sure.  Did I build the airlock facing the wrong direction or something?  It only let me do vertical or horizontal.

[BakerBob]

Pathing through horizontal doors can be tricksy. Select a duplicant and check if the white show path lines can pass through, then check the door permissions to see if duplicants are even allowed through. Then try rotating (90 degrees) the door or swapping the ladders to the left side.

[Zarquan]

1 hour ago, Uncrushed said:

I've gotten that message before, but it was usually obvious why.  Here?  I'm not so sure.  Did I build the airlock facing the wrong direction or something?  It only let me do vertical or horizontal.

Do you have door permissions on the door?  That could stop them from building.

Can duplicants access the area above the door?

[cyberwarlord]

6 hours ago, Uncrushed said:

I've gotten that message before, but it was usually obvious why.  Here?  I'm not so sure.  Did I build the airlock facing the wrong direction or something?  It only let me do vertical or horizontal.

It's the door. Hold it open or place the ladders first.

 

The dupes have no where to stand and build the ladders. Yes they should be able to hold on the ladder and do it but those doors don't allow for dupes to 'reach' through to build like the others.

 

So dupes just can't hold it open while adding the ladder.