Can't connect my subdomain

[sick23]

Hello guys , i have my website running , but now i want to add a roulette to my site , and i want to have a dedicated subdomain to it... so i went to web and added roulette.mydomain.com with DNS support , but altough it creates the public_html to that subdomain i can't access it giving me the error : ERR_NAME_NOT_RESOLVED

Help needed!

[Mr.Erbutw]

you use your own dns , or record in the form subdoman "A" ip