While you didn't list the domain, be sure to check several things. When setting up the subdomain in the A record, use only the subdomain and not the domain in the "host" field. For example... if your subdomain is "shop.mydomain.com", only put "shop" as the host and the IP address in the "points to" field.
Also, any changes to the DNS can take 24-48 hours to propagate globally. If you are still not directing to the correct server, you will need to verify the IP address is correct.
TLH - GoDaddy | Community Moderator Supporting you at x.co/247support