Hi 4rw1n,

re:
> but dont know why now i cant connect that remove that line

The line is an edge where 2 different surfaces are joined together, it's normal that objects made up of multiple surfaces joined together will have edges in them like that.

To remove it you would need to make a single larger surface instead of individual surfaces.

When you have 2 planes that meet there MoI is able to remove edges when those are boolean unioned together but not when you have 2 general surfaces touching like you have here.

- Michael