Problem with new K40 movement.

Hi everyone. Im new to laser cutting and just got a K40 in Im trying to work with. The board is a M2 Nano and I am trying to use K40 Whisperer for the software. I can move the head from left to right all the way across the board. But I can barely move it front to back. Its set for the 400mm by 400mm in the software settings. Im not sure all the other settings.

I took a video here to show what it does when trying to move it. Can you please advise me what to check? The belts seem fine. You can hear the sound it makes when doesnt want to move front to rear.

https://imgur.com/a/AFs3GlT