Just because a puppy is house trained in one place doesn't mean he will be in another. Moving usually means back to Potty Training 101 for a refresher.
My 13.5 year old Lady who has been potty trained for ages and will use both pads an outside interchangeably suddenly wouldn't use her pads when I moved last year.
She apparently did not like the spot I selected for her pads so we had to find one that we could agree on.
I had to pen her with her pads, treat her when she peed, etc, just like she was puppy to get her back on track. It took a few weeks, but we worked it out.