Location not working on SMART Mobile

We have been using Smart Mobile for over a year on Samsung A2 with no problems. However, this week three phones could not read the patrol location on SMART Mobile start patrol. I re-installed Smart Mobile on all of the malfunctioned phones after which only one got the location working now.

What could be the issue

Are other apps able to receive GPS, but not SMART Mobile?

It’s also important to check if the location button in on in the phone settings.