Sometimes, Gmail stops receiving messages until you manually refresh the screen after entering the app. Google’s basic help chart consists of telling you to restart, delete all cache and data, turning on notifications and syncing Gmail. You can also go to Gmail settings of your account and click on “Manage Labels”. Make sure both “Label notifications” and “Notify for every message” are turned on and for more help visit here Gmail Support Number Uk & http://www.gmailhelpline.co.uk/ & http://www.gmailhelpline.co.uk/contact.php