Ensure the Emergency Stop Switches are disengaged by pressing them in and then rotating them out. Then try to enable the controller again.
If the problem persists: If your control box has a ready light, while watching the ready light, click to enable the controller. The exact moment you click to enable, the ready light may blink. You may need an assistant to click to enable while you watch the ready light. Note that your control LED badge may be blue and labeled with different text. The ready light is the only important LED for this test. If the ready light blinks one time like this (this video cycles every 10 seconds, be patient):
The problem is the E-stop loop. Note that the E-stop loop runs through not only the emergency stop switch, but all of the motors as well. This is done to prevent a dangerous situation.