Domains
Verify sending domains so your mail authenticates and lands in the inbox.
A domain is your sending identity. Before you can send from an address like hello@yourcompany.com, the domain yourcompany.com must be added here and verified by publishing the DNS records we generate (a DKIM TXT record, a custom MAIL FROM subdomain, and a DMARC policy).
Verification runs automatically once DNS propagates — you don't click anything. A domain moves through Pending → Verified; if records change or are removed it can fall back, at which point sends from it are blocked.
Re-checked at send time
A domain's status is verified again the moment a campaign sends, not just when you created it. If the domain isn't in a sending-allowed state at send time, the send is blocked with a clear message — so a domain that lapses after a campaign is scheduled won't silently send unauthenticated mail.
Domains feed directly into Templates and Campaigns: the from-address you pick when sending must belong to a verified domain. This is the first link in the contacts → segments → campaigns chain.