Website not mobile compatible

Hi there. I've launched a website for my friend: https://www.thekorntvedkochs.dk On a computer it looks fine. On a phone it looks fine as long as you have https:// in front. But if you only type in www.thekorntvedkochs.dk (without https://) the front page appears with a "Recent posts - not found" and nothing else. Can anyone help? Thanks a ton.