Those are "game objects". First see if they exist by doing the command "gobject near" (in game) when you are near to the entrance.
If they are not there, then they may be missing from the DB gameobject and log that here: https://github.com/TrinityCore/TrinityCore/issues
I'm using 335a, but if you are 7.x, i'm sure there are missing data from the DB.