This means there are Unsent Events on the device. Please check your internet connection. Once proper internet connection is established, the Events should start being uploaded on the Web Application.
While on the Mobile App, tap on the 3-stripes on the top-left of the screen and press on the “Events” option. On this tab you can see all the Events submitted -and if there are any Unsent Events left. By swiping left on each Unsent Event, you can either “[Force]Send” said Event to submit it to the Web Application or hit on the “Delete” to delete the Event.