Very annoying sound problem with Nexus 5

[eprpalmeida]

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?

 

[Rukbat]

Start in Safe Mode. If it still happens, it's the phone, and at least you should try to reflash the ROM (if not bring it in for repair). If it stops, it's an app. Run them, one at a time (run an app, let it run for a day, if it doesn't cause the problem add the next one) until the problem comes back. The last app you added is the one causing it. Check its notifications. It may actually be notifying you of something.