I can think of two things that can cause this (I've had both happen).

1) Try a new sensor wire. If you are getting a locked rotor error, the sensor wire may be bad/not connected securely which does not let the ESC see the hall sensors in the motor. On a related note, the rubber grommet/seal on the Ballistic motors where the sensor wire plugs in has caused me to not get the cable in all the way. I ripped it out of my new one and have had zero issues.

2) There could be 1 or more bad FETs in the ESC. I had one that would sit still unless you bumped it then it would go. Bad transistors.