Roku Timer Not Firing: Observing Method Not Triggered

I am creating a Roku channel. I need to fire a timer and check if device is being verified or not. It can be a complex logic, but you can see my code below. It successfully adding device, and triggers onAddDeviceResult methods. Then startPolling method is running but it doesn't trigger onPoll method so I can't verify the device. How can I solve this problem? Thank you.

sub init()
    m.deviceActivatedLabel = m.top.findNode("deviceActivatedLabel")
    m.qrPoster = m.top.findNode("qrPoster")

    m.deviceSetting = new DeviceSettings()
    m.deviceSetting.initialize()

    m.deviceUUID = m.deviceSetting.getDeviceUUID()
    m.deviceCode = m.deviceSetting.getDeviceCode()

    qrUrl = "url"
    m.qrPoster.uri = qrUrl

    if (m.deviceSetting.readRegistry(m.deviceSetting.deviceActivatedKey) = "true")
        m.deviceActivatedLabel.visible = true
        print "Device already activated!"
        navigateToNextScreen()
    else
        m.deviceActivatedLabel.visible = false
        print "Starting activation process..."
        addDeviceAndStartPolling()
    end if
end sub

sub addDeviceAndStartPolling()
    m.apiTask2 = createObject("roSGNode", "ApiTask2")

    m.apiTask2.SetField("deviceUUID", m.deviceUUID)
    m.apiTask2.SetField("deviceCode", m.deviceCode)

    m.apiTask2.ObserveField("result", "onAddDeviceResult")
    print "Observer registered for result field."

    print "Adding device with UUID: " + m.deviceUUID + " and Code: " + m.deviceCode

    m.apiTask2.control = "RUN"
end sub

sub onAddDeviceResult(event as Object)
    print "Observed change in result field."
    response = event.getData()
    print "Add Device Response: "; response

    if (response = invalid or response.id = invalid)
        print "Failed to add device."
        return
    end if

    m.deviceSetting.setDeviceId(response.id)
    print "Device added successfully. Starting activation loop..."

    startPolling()
end sub

sub startPolling()
    m.attempts = 0
    m.maxAttempts = 10

    m.pollTimer = createObject("roSGNode", "Timer")
    m.pollTimer.duration = 5000
    m.pollTimer.repeat = true
    
    if (m.pollTimer = invalid)
        print "Failed to create the Timer node."
        return
    end if

    m.pollTimer.observeField("fire", "onPoll")
    print "Observer registered for Timer fire event."
    m.top.appendChild(m.pollTimer)

    m.pollTimer.control = "start"
    print "Polling started with a 5-second interval."
end sub

sub onPoll()
    print "Timer fired. Polling now..."

    if (m.attempts >= m.maxAttempts)
        print "Max attempts reached. Stopping polling."
        m.pollTimer.control = "stop"
        return
    end if

    m.attempts = m.attempts + 1
    print "Polling attempt: " + m.attempts.toStr()

    m.apiTask = createObject("roSGNode", "ApiTask")

    m.apiTask.SetField("deviceUUID", m.deviceUUID)
    m.apiTask.SetField("deviceCode", m.deviceCode)

    m.apiTask.ObserveField("result", "onVerifyDeviceResult")
    m.apiTask.control = "RUN"
end sub

sub onVerifyDeviceResult(event as Object)
    response = event.getData()
    print "Verify Device Response: "; response

    if (response <> invalid and response.activated = true)
        print "Device activated successfully!"
        m.deviceSetting.writeRegistry(m.deviceSetting.deviceActivatedKey, "true")
        m.deviceActivatedLabel.visible = true

        m.pollTimer.control = "stop"
        navigateToNextScreen()
    else
        print "Device not activated yet. Retrying..."
    end if
end sub

sub navigateToNextScreen() as void
    print "Navigating to the next screen..."
end sub

I tried adding Timer into xml file. But still it didn't work.

I believe your issue is this line:

m.pollTimer.duration = 5000

The Timer component takes duration in seconds, not milliseconds. (see this docs page).

duration: Specifies the time in seconds before the Timer node fires after the control field value is set to start. To specify time values down to millisecond granularity, use a float type (0.001 equals one millisecond)