Each custom domain shows the DNS records it needs, with the exact Name/Host and Value/Content to enter at your provider. Two things are being checked: that the domain resolves to our servers (CNAME, or ALIAS/ANAME on a root domain) and that a verification record proves ownership.
Statuses
Pending — the domain was added but hasn't passed verification yet. Active — verified and serving. Failed — the last verification attempt didn't pass; open the DNS records, compare them against your provider's settings, and verify again.
Common failure causes
DNS changes still propagating (can take up to a day at some providers), a record entered on the wrong host name, an old conflicting record still in place, or a proxy/CDN in front of the domain rewriting its records. The verification error names the record that didn't match — fix that one and retry.