This error message Pops out, when the manager configures the application to Round the Clock in time to nearest (X minutes).
Example: If the employee clocks in at 4:43 PM when the Rounding is set to to nearest 10 minutes. The system will save his clock in time as 4:50 pm instead. Now, when the employee will attempt to clock out the system will not allow him to clock out before 4:50 pm.
Note: The manager can change this behavior from Settings->Time clock