Setting up subdomain sites / DNS?

Hi – I’m hoping someone might be able to help me with multisite as I’ve got stuck. I’m fairly new to wordpress generally, but learning quickly, and am not a coder.

I’ve gone through the installation steps, adding code to htaccess/wpconfig etc. Everything looks fine and I’ve got my network admin area.

My main site is ymes.org.uk and the second site I’m trying to create is shop.ymes.org.uk

Through the network admin panel I’ve gone to create a site and entered the required details (site address, site title, admin email) and seemed to have added the site successfully. However, clicking through to see the site on shop.ymes.org.uk or enter the admin area at shop.ymes.org.uk/wp-admin shows a ‘cannot display this webpage’ message.

I read that the additional sites are virtual so do not need folders creating for them in the public_html folder of the site. I do have access to this if necessary though and I’m hosting on 123-reg.

I wonder what I do need to do on my hosting? I’ve tried setting up a subdomain in my hosting package – not sure if this is the right thing to do. I’ve pointed it at the public_html top level folder. This hasn’t worked though.

I don’t know that I need on-demand / wildcard subdomains, as I’m only going to be setting up one or two additional sites? Although let me know if I’m wrong!

Any help would be appreciated 🙂