Hi, I have a Nexus 5 32gb for 1 year and 3 months. Since last week my cellphone starts to ring randomly (the ringtone of my alarm) with no notification on screen. It only goes off if I press hold or pressing the screen if it is unlocked. I have put all volumes to zero, set the priority to No interruptions but it still rings randomly (my house, my class, everywhere). This is making me crazy! Can you guys help me please?