A little help in my dns setup for cname

Ok, here is the problem. When a client tries to go to my website and types in www.tesselate.us responds as a non-working destination. If you type it in as tesselate.us, it goes to the website. My hosting and website is being managed on godaddy if this helps any. I did go in the help app and went to domain management and then to DNS records.I created a cname for www with the value set at @. It’s not working I think. What am I doing wrong? Some guidance for this old man would be most appreciated.