It sounds like your motor may be dead - have you pulled the brushes out to check n how dirty the comm is? How long did it live before it died (did you get a couple of weeks, months, ?). I'm just trying to figure out if your motor was due to pass on or if something happened early. Either way your first step will be to replace the motor - I'm assuming that you still have the factory motor.

I'll try to help you figure it out but the more information you share the easier it will be. What (if anything) did you last do before it died? (Did you oil it - could oil have gotten on the comm (that would short it), are the brushes hanging up or do they move smoothly, does it only happen when you try to run or does the ESC get ot when you aren't on the throttle?) Anything you can think of might help to zero in on the problem without spending money trying stuff that doesn't work first. It sounds like your motor just died but more information might confirm or deny that.

Do you have access to a good ohm meter (bench quality)? You could check the resistance of the motor - if it's good it will read 1/2 an ohm or so more or less (not counting the resistance of the test leads) - if it's dead it will read the same across the motor as it does if you short the test leads together. (That's why it takes a bench quality meter - an inexpensive meter won't tell the difference between 0 ohms and 1/2 ohm.)