android - Diagnose alarm failure on HTC One / lollipop -

i developing alarm app works on every device i've tried except htc 1 android lollipop. app ui works expected, when alarm due ring, nothing happens, no sound , no "stop" button.

unfortunately htc 1 not mine, have infrequent , brief access it, can't connect pc view logs. have genymotion, has emulation of htc 1 android 4.4. alarm worked on that. i've tried both xperia z , galaxy siii both lollipop, , worked fine on those. worked of variety of other devices earlier versions of android.

so hoping possible explanations, or possible mechanisms diagnosing problem. or perhaps alternative device available in genymotion has key features in common htc.

edit: fyi phone not rebooted between setting of alarm , time alarm ring. indeed test setting alarm go off in 1 minute.

edit: app old unfinished project resurrecting. have been using beta version own personal alarm (not wake-up, meetings on specific dates, , count-down timer too). has worked reliably me on year without problem, on galaxy sii , siii. alarms remain active after powering down , rebooting.

have tried cleaning cache of app? have had similar experience on 4.4 various apks not working , simple solution clean cache of app

-penina mezei