CNC stops in the middle of my job

I just finished assembling my machine and I have tried to run 2 of the sample products. The program starts and runs for about 15 seconds and stops. I am running gSender 1.2.2. The router and control board are on different electrical circuits. The screen shows the current position of the router and that it is Running. All of the jog controls are greyed out. Is this an issue with gSender? Something else I should consider?
Thanks for any help.