Set up your domain with 123-Reg
If you've bought a domain from 123-Reg, you must reconfigure your DNS settings to point the domain at your Shopify-hosted storefront.
Before you begin
After you've added your domain and set it up with your third-party provider, it can take up to 48 hours for changes to take effect. You can check the status of your domains on the Domains page in your Shopify admin.
Setting up your root domain with 123-Reg
Log in to your 123-Reg control panel.
Select the domain you want to configure from the Your domains drop-down, and click Manage:
In the Advanced domain settings section, click Manage DNS:
Click Advanced DNS to view your DNS records:
Click the edit entry button (to the right of the destination/target column) for both the @ and * records.
Change the Destination/Target to Shopify's IP address: 18.104.22.168.
Save the changes. Your records should look similar to this:
To set up a new subdomain:
Scroll down to the blank Hostname field.
In the Hostname field, enter the subdomain you want to configure. In this example, we're using the www subdomain.
Under Type, select CNAME.
In the Destination CNAME field, enter your complete myshopify.com URL:
Click Add. Your DNS table should look similar to this:
If you want to add other subdomains, repeat the above process. For example, if you want to have shop.yourdomain.com as a subdomain, enter shop as the Hostname, and enter your myshopify.com URL as the destination, as above.
If you are not able to edit your DNS records from within your domain provider's admin, you've probably pointed your domain's nameservers to a third party. To resolve this issue, you must contact your domain provider to have them point your domain's nameservers to their default nameservers.