1. First, check to make sure the phone’s data access is still available by using the phone’s browser to access the internet..
  2. Turn off the wifi access to see if the 3G/4G data access is still working properly..
  3. Make sure the phone is not in airplane mode.
  4. Check to make sure the app is still running on the phone by going to Settings > Applications > Running Application. Make sure the running time is slowly ticking up.
  5. Check to make sure the app is still installed on the phone. Go to Settings > Applications > Manage Applications and look for the app in the list.
  6. Try doing a hard reboot of the phone by powering it down and removing the battery for 10 or 15 seconds. Then reboot.
  7. Make sure the time and timezone are correct for the device.
  8. Check to make sure battery optimizer apps aren’t killing SMS Tracker.