Not sure on horizontal either.
My folks have a Shorestation lift and here’s a couple common items.
Cable is spooled on to itself. Cure – good leather gloves are a requirement. Get some slack in the cable and get it unseated by hand.
Just kind of stuck due to rust or inactivity. Cure – One person stand on the side that won’t go down. Use body weight, jumping, swearing, jiggling the cable, just get it moving. Lather, rinse, repeat. Always bring it up under tension.
Still sticky or stuck – add some WD40 or other anti seize spray.
Still having issues then check for binding in other places.
What we found is that the lift had sat idle for a couple years. It just needed to be run through it’s paces, a little lube, and occasionally have to unbind the cable. It’s working way better their third season than the first.
Good luck