Zoom is stuck

That cord may have been a gasket for sealing the lens from dirt.

Try taking the lens off and remounting it.

Try cleaning the lens gently with a lens cloth or maybe a damp paper towel? Other than that - you may have something stuck in your lens that is making everything blurry when you zooom in...or the lens may need to be replaced to be fully functional. Do you notice any blurry spots when you zoom out that get bigger when you zoom in? If so something may be stuck in your lens. Good luck!

Some Sigma lenses feature a "zoom lock" to protect the lens when not in use, so just make absolutely sure that this hasn't accidentally been left engaged nor that the switch is being obstructed from unlocking somehow, such as by dirt/debris. It's also worth giving the lens a few sharp taps down onto a table in case it's just a bit of sand or other debris.

Otherwise, it's not a DIY fix due to the complexity of modern autofocus zoom lenses. If you try to force the lens or attempt an incompetent repair you'll ruin a £300 lens.

The best option is to send it to Sigma for a repair estimate, if you're in the UK then there's a fixed fee of £93.99 (tariff no.6). The link I've provided is for the UK but if you're elsewhere different fees and procedures probably apply. If it helps, my experiences of getting similar repairs done in the north America is that they're usually a bit cheaper and in Aus/NZ they're a bit more expensive.

If your lens has failed under warranty then the repair is free if the lens has not been misused, there is no evidence of any unauthorised repair attempt, and you have proof of purchase.

Don't force it.
Did you get dust or dirt in it?
The only solution is to bring it in for service or send it to Nikon if it is a USA model.
Nikon USA will NOT repair any gray market items.

First thing: Don't try to zoom it at all anymore. The mechanism inside is broken or somehow disconnected, and you can make it worse by trying. Please take it in for repairs as a camera pro will need to look at it.

Hi I had the same problem with a codak C743. I cleaned the lens casing from out outside as much as I could and sprayed a tiny bit of WD40 making sure not to get it on the lens itself.

Then I kept turning it on, and zooming in and out until I got the lens error message, switched it off, the on again, wipe, new WD40, zoom etc. repeated this s number of times until the lens was freed.

I think I had some sand/ dirt around the casing.

Worth a try I guess.

Is there a little lock switch on the lens?? My Nikon lens all have a tiny little lock and if it accidentally gets pushed into lock position it will not zoom. Barry Brown www.coralreefphotos.com

Are you sure it's the zoom ring that's stuck, and not the focus ring? The focus ring doesn't move when the camera is in autofocus.
If it's indeed the zoom ring that's stuck, you can spend more money than the lens is worth in repairs, or buy a replacement (circa 35 dollars on ebay) for dreadfully cheap. Good luck.

This sounds like there is debris lodged in the zoom gears. Been to the beach lately? The gears in the zoom mechanism are very small, and even a tiny spec of sand or other debris can jam them up. Alternatively the sensor inside the lens that feeds back the position of the lens to the control circuit may be failing - so the camera thinks the lens has retracted all the way and stops. If the stoppage of the zoom action is abrupt then it is probably debris, if it is a smooth stoppage like the camera is stopping on purpose it is probably a position sensor. Either way the camera will require repair. David Millier Advance Camera Repair