Domain registration

Your domain is the foundation of your email and website. If it expires, mail bounces and the website goes dark, and in the worst case someone else can register it and receive your mail. Keeping the registration current and knowing who controls DNS prevents the most expensive kind of outage: the quiet one that happens over a holiday weekend.

The nameservers show where DNS is actually hosted, which is often different from the registrar. That is the account where SPF, DKIM, DMARC, and website records are edited.