Make sure the servo is in channel 1. ESC in channel 2 (1 to turn, 2 to burn) and make sure they are plugged in the right way.
After, is the esc giving power to the motor? Make sure all motor connections are plugged in and tight.
Might have to calibrate the esc to the new radio.
Normal esc calibration.
Hold the set button or esc button. Hold until it beeps
Do neutral press button
full throttle, press button
full reverse, press button
And it should be re-calibrated
Also before, good thing to do, make sure battery is fully charged and cells are balanced.