Pixhawk hardware issue

I recently got a new pixhawk cube. I was testing my motors and it was working fine. I plugged my USB cable to my computer since I was testing it with my mission planner while the battery was plugged in. After that , I cannot not see my motors running while following the same method as before. The pixhawk stills turn on. I can connect to mission planner. But motors won’t turn on. I borrowed another PIXHAWK from my friend to see , if I get the same issue with that. But, everything is working fine with that one. So could you guys please let me know what the issue is or can I get replacement for that one. Thank you