Your too far away, means your Click to Move is off.

The wizard gets you an IWT key, with two steps.
Step one turns on Click to Move.
Step two turns off Click to Move.
Somewhere after it is enabled and before it is disabled, it sends IWT to your toons.

My version is executed as a Do Mapped Key action.
And not its own mapped key that is executed on press and release.

Basically, you need to have Click to Move enabled for it to work.
Interface Options - Mouse - Check 'Click to Move'.
Or /console AutoInteract 1

Probably then change the IWT Mapped key to one step.
That sends IWT to all windows.
Nothing about enable/disable Click to Move.

That gets you.

A:
IWT key, push this once and every does IWT with my target.
Excellent for quest givers, inn keepers, flight masters, corpses to loot, etc.

B:
IWT built into melee.
Press DPS keys and melee also IWT.
With a toggle to enable/disable the auto IWT as part of your DPS.

(Note: Auto in the sense that it is built into, not that it happens without your pressing a separate key to cause it to happen... the key pressed is just also doing DPS).