You have built a corridor but there is a weird gap between your subassemblies in 3D that is not shown in the Assembly on your drawing.
You may have accidentally introduced an Offset into your subassemblies.
Offsets can be accidentally introduced if you have grip edited your subassemblies instead of only moving and copying them with the right click menu options.
Right click on each of your subassemblies in the area of the break on your assembly. And those that have the option 'Clear Offset in Assembly' NOT greyed out, click on that option to clear it.
This will move the subassembly to where it is actually located, then you can use the right click options to move it to where it should be.
Subassemblies should not be grip edited.