The most common alarm is Alarm 2. When the E3/E4 homes it sets limits in the firmware. These soft limits will trigger and not the machine to move past the end of travel on each axis. When the E3/E4 is homed, the axis is set to X=0, Y=0, and Z-0.

Firmware settings $130, $131, and $132 set the maximum travel for each axis. The E3/E4 default settings are X=450 Y=390 and Z = 85