Hobbywing Xrotor ESCs not calibrating?

Hi, I am building an octocopter using a Tarot T-15 frame with a Pixhawk cube FC and Hobbywing 40a ESCs. When I try to calibrate my ESCs, they do not respond in any way. They give off a continuous regular beep and twitch no matter what I do. This is my first project and there for am at a bit of a loss of what to try. I have calibrated the radio and my pixhawk is hooked up fine to the mission planner. Any ideas I can try? Thank you much.