For OPPO F9 Pro

Step 1: Go to settings --> Advanced Settings --> Battery Manager --> Protected Apps, then find “MyGate” and "Protect" it. This is essentially "Whitelisting" the app, aka telling Oppo, "hey, this app is useful, please don't kill it."

But that's not enough. Oppo's software will still kill the app unless you take two more steps.

Step 2: Go to Settings --> Apps --> Advanced --> Ignore Battery Optimisations, then find MyGate and ignore it. Don't be tricked by the misleading wording, "Ignoring" the app actually means allowing it to run, because you're telling the battery optimisation function to "Ignore" that app.

Step 3: Go to Settings --> Notification Panel & Status Bar --> Notification Center, then find MyGate, then activate "Allow Notifications" and also "Priority Display". You have to activate the priority part too to make sure you get notifications. 

Step 4: Lock the myGate app in the "Recent apps overview" panel, so that it is essentially always running in the background. 

Post this, you can also perform Test Notifications on MyGate app by following the below steps:

• Click on 'Household' on the home page of your MyGate app screen.
• Scroll down and Click on 'e-Intercom Setup'. Click on 'Send Test Notification'. You will receive a test in-app notification.

If a Test notification is triggered on your phone, then the notification issue has been resolved.