Xcode – Background fetch with BGTaskScheduler works perfectly with debug simulations but never works in practice

I register the background fetch task in didFinishLaunchingWithOptions of the appDelegate:

BGTaskScheduler.shared.register(forTaskWithIdentifier: BackgroundScheduler.shared.backgroundTaskId, using: DispatchQueue.main) { task in

    BackgroundScheduler.shared.handleAppRefresh(task: task as! BGAppRefreshTask)
}

The handleAppRefersh function schedules for another refresh task and calls the fetch method of the operation and also passes a completion handler to be run after finishing the fetch operation.

func handleAppRefresh(task: BGAppRefreshTask) {
    
    os_log("handleAppRefresh exetued.")
    
    scheduleAppRefresh()
    
    task.expirationHandler = {
        os_log("backgroundFetch expiration called")
    }
    
    operation.fetch() {
        os_log("backgroundFetch fetch called")
        task.setTaskCompleted(success: true)
    }
}

The scheduleAppRefresh submits BGAppRefreshTAskRequest for repeating the background fetch executions.

func scheduleAppRefresh() {
    
    os_log("scheduleAppRefresh exetued.")
    
    let request = BGAppRefreshTaskRequest(identifier: backgroundFetchId)
    request.earliestBeginDate = Date(timeIntervalSinceNow: AppSettings.refreshInterval)

    do {
        try BGTaskScheduler.shared.submit(request)
    } catch {
        os_log("Could not schedule app refresh:", error.localizedDescription)
    }
}

The refreshInterval is 10 * 60 which means 10 minutes.

The operation.fetch method checks the current location of the device and sends a request to a remote server. Finally it sends local notifications, updates UI and calls the following code:

task.setTaskCompleted(success: true)

Both the "Location update" and "Background fetch" capabilities checked in the Xcode and required settings added to the info.plist.

When I test the background fetch feature using the following debug command everything works perfectly and there is not any warning messages in debugger.

e -l objc -- (void)[[BGTaskScheduler sharedScheduler] _simulateLaunchForTaskWithIdentifier:@"TASK_IDENTIFIER"]

But when I leave the app in the background even for long hours, the iOS never calls the handleAppRefresh function.

Xcode: 12.2, iOS: 14.2

Project public repo:
https://github.com/amirrezaeghtedari/CoronaVirousRegulations.git

I’m confused completely.