Owning a Car in Different Province

We live in Nova Scotia but spend many months each year in Alberta. So we purchased an inexpensive car to leave at our son’s house in Alberta….it is registered in Alberta. We have Nova Scotia Drivers licences and so we were told by (one) insurance company that we can’t buy auto insurance unless the car is registered in the same province as our drivers licence.

Is this universally true or should I be trying other insurers?