PreArm: Motor Interlock Enabled

Hello everybody I was following a drone building tutorial on udemy and encountered a problem. As I was trying to arm my drone I have repeatedly received the message “PreArm: Motor Interlock Enabled”. I would like to get my drone flying. I have also encountered a problem were all the motors seam to be stabilizing the drone but one motor fails to provide power to spin the prop sufficiently.

Thanks for checking this out. Please let me know if you can help