Apple has confirmed it is working to fix an issue that is causing some iPhone alarms to not play a sound, after users who overslept raised the glitch on social media. The alarm, built into the Clock app of the device, is the wake-up tool of choice for many iPhone users. However, in recent days, a number of iPhone users have reported that their alarms have not gone off, causing them to be late for work and school. Apple has confirmed it is aware of the issue, and said it is working to quickly fix it. It remains unclear how many people have been affected, what may be causing the issue, or what, …