Depending on where I am at location-wise, the app. can freeze.  There are plenty of dead zones in my area, so I often have to wait until I reach a live zone or manually enter on the portal later.  There are several questions and options in the procedure of clocking in and out as well.  These options and questions make for a higher chance of freezing before getting fully clocked in.  It can be very time consuming just to clock in and out if you are able to do it at all.