Smartphone sales have stagnated over the past few years and even started to decline as newly released phones struggle to provide any great leap forward in functionality and design. Then along came foldable phones in the first half of this year — but as it turns out, making them is hard and Huawei Electronics Co. Ltd. is now the latest to struggle to deliver.

The company told a press gathering in Shenzen Wednesday that the Mate X, its first entry into foldable smartphones, has been delayed again. TechRadar reported that it likely won’t hit the market until after November, though Huawei is still claiming it’s scheduled to launch between September and November. It was originally scheduled to launch in June.

The phone, complete with a $2,600 price tag, was revealed a week after rival Samsung Electronics Co. Ltd. announced its Galaxy Fold Feb. 20. Unlike Samsung’s version, which included a rear screen and opened out like a book, the Mate X has a screen on one side, only allowing users to use half the phone or to expand it out to use the larger form factor.

Initial reviews comparing two phones tended to be more favorable to the Mate X even before Samsung started having problems with the Galaxy Fold.

Problems with the Galaxy Fold first emerged when review units sent to tech reviewers in April started to break after only two days of use. After initially denying there was a serious problem, Samsung delayed the release of the phone April 22 before canceling pre-orders May 7. Samsung is expected to release the phone in September.

Huawei’s problems with its phone, like Samsung’s, appear to have been engineering-based, with both companies seemingly failing to do proper testing of key components prior to announcing the products. Witnessing Samsung’s problems, Huawei has taken a cautious approach to the Mate X and is said to have made a number of changes to the phone, including refinements to the device’s hinge.

Image: Huawei