Be extremely careful, while configuring DNS settings. If you add a new domain, delete all A-records. If you want to add a subdomain, don't delete records, because you can disrupt the site.
DNS is distributed all over the world to make your domain work. Note: It takes a few hours for a new domain to become active.
Try to set up your DNS correctly and if you want to change your purchased DNS, send a request to support center.
More information about domain types you can find here: