Why do my alarms not ring sometimes?

iOS:

• Please make sure that the notifications are enabled for Galarm.
• If "Enhanced Notifications" setting is disabled, then alarms don't ring when the phone is on silent.
• If the "Enhanced Notifications" setting is enabled, then alarm ring even when phone is on silent. However, if you are on a phone call when an alarm was supposed to ring, then the alarm is rung using a simple notification.

 Android:

• Some Android phones have some settings that don’t start apps automatically when the device restarts and don’t allow the apps to run in the background. 
• Based on our findings, below are the settings on some phones that should be modified to rectify the problem.
  
  

  Manufacturer	Android OS	Instructions
  Asus	-	click here
  Huawei	8 and above	click here
  Huawei	7 and below	click here
  Mi	-	click here
  Nokia	9 and above	click here
  Nokia	8 and below	click here
  Oppo	9 and above	click here
  Oppo	8 and below	click here
  Realme	-	click here
  Samsung	11 and above	click here
  Samsung	8 and below	click here
  Tecno Mobile	-	click here
  Vivo	9 and above	click here
  Vivo	8 and below	click here
  Android, in general	-	click here

   
• For vendors not listed above, and to learn more, please visit www.dontkillmyapp.com