One person wrote on Twitter: "NHS Covid-19 app #loading notification appearing on android mobiles. Some concern that contact tracing may not be operational." Another said: "Has anyone else's NHS Covid app got stuck such that it's showing a permanent 'Loading' notification in the notifications tray?" A third said: "My android phone is displaying a notification from 1am this morning that says 'NHS Covid-19 Loading...'. "Nothing is happening and I can't remove the notification. My wife has deleted the app to get rid of it." NHS Covid app loading notification: Why does my Covid app say loading? (Image: GETTY) Users are receiving this notification (Image: TWITTER)