Some of my stands do not connect to security:
However, security connects to them:
Try putting the larges doors. I think you’ve blocked your entry and exit squares with walls.
Can you turn on the zone overlay (Key Z)?
Most common issues is that the door is not marked as security zone.
And as @LEI wrote, the door needs to have 4 fields as entry and exit will be on the left and right side. (Beta 3 will show that better)
/edit… ah I see, at the lower stand you have already those indicators:
As no-fun said, can we get some screens with zones enabled?
I had some similar issue.
FIRST set Stand to commercial
After that connect boarding desk to stand