Apple Inc. (AAPL.O), in an unprecedented retreat, canceled its highly anticipated AirPower wireless charging mat and apologized to customers who were waiting for it.

The device, which was intended to charge an Apple Watch, iPhone and AirPods all at once, was originally announced alongside the iPhone X in September 2017. At the time, Apple said it would go on sale in 2018. While the accessory isn’t as crucial to Apple’s bottom line as an iPhone, iPad or Apple Watch, the decision to cancel an announced product is an embarrassing and rare move for the Cupertino, California-based technology giant.

“After much effort, we’ve concluded AirPower will not achieve our high standards and we have canceled the project,” Dan Riccio, Apple’s senior vice president of hardware, said in a statement provided to Bloomberg Friday. "We apologize to those customers who were looking forward to this launch. We continue to believe that the future is wireless and are committed to push the wireless experience forward."

Apple didn’t say why exactly the product was canceled, but people familiar with its development told Bloomberg last year that the company faced challenges with the software, overheating and the ability to charge multiple devices on any spot on the mat.

The AirPower would have been another accessory for Apple’s growing Wearables, Home and Accessories segment, which it’s counting on to augment sales of the flagship iPhone. The new AirPods launched earlier this month referenced the charging device in their packaging.