Hello. The Maestro user's guide documents what a blinking LED at startup means:
This makes me think that you are having a power problem that only manifests itself when the servo draws a lot of current as it tries to move. If you are using batteries, please make sure they are freshly charged. Also, I bet you have your batteries connected to the Maestro's VIN; it would help to disconnect VIN because then the Maestro's processor can just be powered from USB.
If you continue to have trouble, please provide all the details about your setup, including pictures.