'connect' tool not working

[Anonymous]

Trying to use the connect tool to create two lines down the side of this box. However, the command keeps bending the lines and sometimes doesn't click on edges. Does anyone know a way around this? I've tried re-modelling it several times but it's just a box so it doesn't have anything to do with hidden lines etc. 

[CAMedeck]

The edge at the very top is shorter than the rest of the edges.  They all reach from one side all of the way to the other side of your box.  However, because you've added some details to the top of the box, the length of that edge is shorter, subtracting the edges that are part of your details.

You could manually align the new Connected edges to make them a straight line, or try the Slice Plane command in the Edit Poly modifier.

[Anonymous]

Not sure what you mean by "doesn't click on edges".  Be sure you select a ring of edges, not just one or two, to connect.  I'm sure you know this already, but just in case: select an edge, then ring, then connect.  It does appear from the screenshot that your top loop of edges are scaled in slightly?  If this is a default box, then that shouldn't be the case, unless you manually scaled the edge loops at the top.  What happens if you try using the Swiftloop option instead?