LOFTING A SERIES OF CURVES

Hi floks!
I managed to sweep2rails between a pair of curves and a line I created from their starting points.

But when I try to repeat the process for a group of lines it just doesn't work.

Someone might think using a developable loft would do the same, but actually the definition gives a warning error when I try to do so.

Just realized that using a "straight" loft does what I want, but still wondering why sweeping the group of lines doesn't work.