Welcome to the forum!
The "Search" function on this forum is your friend. Here's a link to a thread about a problem similar to yours with some useful suggestions:
http://www.hilotrailerforum.com/f22/solenoid-1993-31-a-4264/index2.html
Do you have an Owner's Manual? If not, you can find one, or a close model year, at the forum home page, near the bottom of the page under the "Library" section.
Have you watched the operation videos on YouTube? Here's one on raising/lowering, other videos can be linked from this one.
Have you lowered it previously, that is, do you know the correct position of the switches, etc.?
Possibilities: Bad lowering solenoid, bad wiring, bad switch, bad battery (doubtful if new, but it's not unheard of to buy a defective battery), binding safety bar, operator error!
Good luck, let us know what you find.