If you have Battery Saving setting ON (enabled) the automatic upload won't continue while the myCloud app is in the background. You will need to start the myCloud app again. Still, we want to remind you about that and that's why you will get the notification like this one:
If you don't want to see this notification any more, you can hide it in the “Backup” channel in the notification settings for myCloud app, as shown here:
You need Android 8 or above to be able to set the notifications for myCloud app.