Custom domain not working correctly on heroku rails app

I have a domain on godaddy ad i want to put it in action on my heroku application i followed this video and it worked correctly but the problem is that i can only acces my website at www.example.com and when i call for example.com it takes me to a godaddy page saying: "You've registered your domain.Now put it to work." and when i tried https://example.com or http://example.com it got me error

Any help?