Since I` updated to lollipop, my alarm can`t sound when I have my phone on mute ... And I don`t know why, because before it wasn`t that way. I could get the alarm sound even if the phone was on mute..
Check the alarm volume or simply take your phone off mute. There's no reason that Lollipop should have that issue on your phone because alarms are supposed to bypass mute/vibrate only as long as you have that setting enabled. Otherwise, I don't really know what to tell you. It could be a software issue for your phone specifically.