Subdomain not showing in browser

Hi

I have created a multi store and followed the intruction from opencart 'Creating a multi-store'. I also made all the neccesary adjustment in my admin panel and when checking the subdomain in the browser it doesn't show up and I get this message

'This webpage is not available'

Am I missing a bit? Or how long does it take to take effect?

Help more appreciated
Thanks

From changes made in the registrar account (or elsewhere not sitting in a redirection on-site, as in .htaccess), propagation among nameservers (they update each other) of dns and forwarding changes takes up to 72 hours to be effective half-way around the world, probably usually 12-24 hours regionally, 48 hours continentally. Meanwhile, traffic goes through both updated nameservers that already know and not-updated nameservers that are still clueless. Subdomains are set up in the first instance in the registrar account (which may or may not be the same outfit as your webhost and account). If you didn't reset the registrar, where all traffic direction en route to (sub)domains, nameservers will have no concept of what you want to see happen.