Amazon.com Inc. is delaying the public opening of its first cashier-less convenience store because of technical complications.

Amazon Go was due to launch to the public by the end of the month, after launching in beta mode to employees in December, according to people familiar with the matter. It is unclear when it will now open, as it works out kinks in the technology to automatically charge customers when they leave, instead of needing to have cash registers, checkouts and lines.