Not all registrars are able to support the new Blogger domain ownership verification requirement. Some registrars won't allow a second "CNAME" in the same subdomain - and others can't handle the excessively long target address. Ever since Blogger added domain ownership verification, we've been seeing complaints from some blog owners, who have purchased domains directly from registrars who can't provide the required DNS addresses on their servers. Even though not all registrars have DNS servers that will provide the right DNS address entries, most registrars will allow us to use third party DNS servers. The use of publicly available DNS servers, which can provide the required DNS addresses, will eliminate the need to transfer domain registration - when the registrar is unable to provide the right DNS addresses , using their own servers.
What Blogger won't tell you