I had that problem several years ago and it turned out to be the inline fuse that kept blowing. They walked me thru the steps to operate the jack and to bypass the fuse. It also had a resettable breaker.
I have found that it is a lot better to call their tech support than to send an email. I called and got a live tech and when I told him I was in a campground in north central Washington state and it was 10 degrees and a foot of snow on the ground and still snowing, he told me a couple of things to do for now and that he would call me in the morning and eslk me thru the rest. Wow and he did.