tool.cloud-mail.jp has no CNAME records.
Question and response
Question
dig tool.cloud-mail.jp. NS
Answer
The response has no answer records.
Authority
CLOUD-MAIL.JP. 644 SOA NS21.FreeBit.NET. root.FreeBit.NET. 2026012201 3600 900 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0