For Samsung Phones

Notifications not delivered is due to adverse device settings. The first thing that you will need to do in this particular case is to make sure that the notification settings of the phone is properly set. 

1. Take note that if you have a Microsoft Exchange Activesync account set up on the phone then the lock screen notification will default to “Do not show notifications”. What you will want to do first is to navigate to Apps – Settings – Lock Screen and Security. Tap the Notifications on Lock Screen then tap Content on Lock Screen then make sure show content is enabled. Also if you have a company MDM software installed, please get myGate whitelisted.

2. If you have battery optimizers such as Greenify, Clean Master etc installed please whitelist myGate app in them

3. You will also need to check the notification settings of myGate app

• From the home screen, tap Apps.
• Scroll to and tap Settings.
• Scroll to and tap Notifications.
• Tap to enable  myGate.

4. In case the settings are correct but the issue still occurs then the next step is to check if an app you downloaded is causing the problem. To do this you need to start the phone in Safe Mode. In this mode only the pre-installed apps. If the issue does not occur in this mode then it could be caused by an app you downloaded. Find out what app this is and uninstall it.