1. whois
[Domain Name] WEBNT.JP [Registrant] KADOKAWA CORPORATION [Name Server] ns01.dns.kadokawa.jp [Name Server] ns02.dns.kadokawa.jp [Signing Key] [Created on] 2015/09/02 [Expires on] 2023/09/30 [Status] Active [Last Updated] 2022/10/01 01:05:07 (JST) Contact Information: [Name] KADOKAWA CORPORATION [Email] gm-isys-domain@ml.kadokawa.jp
http://dnsinstitute.com/research/dangling-mx/dangling-mx-nxdomain-provider-domains.html
2. history
webnt.jp. 600 IN MX 10 webnt-lb-122207289.ap-northeast-1.elb.amazonaws.com.
$ dig webnt-lb-122207289.ap-northeast-1.elb.amazonaws.com