580EX doesn't recognize my focal length

I try setting the flash zoom to the mode where the flash head zooms in and out depending on my zoom lens's focal length, but now it just reads "Zoom -- mm" and the rectangle icon on the right of "mm" that signals it has "auto-detected" my sensor size doesn't show either. If I switch to manual zoom the flash can be zoomed in and out manually. Does anyone know how to rectify this issue? I'm using the 17-40 f/4 and a Rebel XT.

Thanks!

Is the plastic thing (i have no idea what its called) pulled out covering the flash?

no. I do pull out the bounce card, but i push the plastic wide angle diffuser back in. Perhaps i didn't put it back in all the way?

I have no idea, but try pushing both the bounce card and the wide angle diffuser back in, then see if it works.

If the flash head is not pointing straight forward it doesn't indicate the focal length. At least that is how it is with a fixed focal length lens. I'm not sure if it's the same with a zoom lens.

TMR Design, you are correct. Thanks for explaining this nuance.