Assembly locks degrees of freedom

Hi

I'm trying to learn assembly in SW. I have linear rails in a 3DOF gimbal that works fine in Creo, but when I use the exact same mates in SW it locks up 2 of those DOF.

Only forward and backward still works as expected. Up and down and left and right locks up.

What can I investigate to fix this please?

Thanks.

Gimbal1.PNGGimbal2.PNG

SolidworksAssemblies