The most likely reason for this is that Location Services is not switched on and therefore the device is not receiving GPS data. To turn Location Services on please follow these instructions.
1 - Go to the Settings icon on the iPhone/iPad
2 - Then look for Privacy - the icon is a little hand
3 - The first item on the menu is Location Services. When you tap it there is a master switch at the top which should be in the 'on' position.
4 - Look down the list of Apps (alphabetical order usually) and then make sure that iFootpath switch is also set to 'on' (switch to the right)
If you need any help please try this Apple Guide: