The exclamation mark next to the employee activity means that there was an issue detecting the employee's location when they checked-in/out. This is usually due to location services being disabled on the device or Wi-Fi being off.
Please have the user check to make sure that location services are enabled on their device by following the steps below:
1) Open the iPhone settings application
2) Go to "Location Services" (Under "Privacy" for iOS 6.0 and higher)
3) Make sure location services is set to ON
4) Make sure TimeStation under location services is also set to ON
Users should make sure that Wi-Fi is enabled even if it's not connected. When Wi-Fi is Off, the device has to rely solely on GPS signals which take longer to acquire and may not always work indoors.