Maker Made motors don't respond

I’ve managed to connect via Ground Control on my Mac.
Error message tells me to adjust chain lengths. when I try, the motors don’t move and it says “the sled isn’t keeping up” then stops.
The connections seem fine and, I assume, if one was bad the other should work a little. I’ve tried both auto and manual adjust. No help.
I see some are using a web based control software but the instructions make my head spin!
Please help.

the connections can sometimes be difficult to click in all the way. Double check all connections are well seated. If you unplug the motor, does it give you the same error?

Make sure that you are using a good USB cable to go from your Mac to the Arduino. -For me that has been the connection that has caused the most problems.

Please send a picture of the power connection going into your controller.

Thank you