domain_not_verified
HTTP status: 422
What happened
A live key used a sender domain that is not verified. Verification needs every stored DNS record to be valid: the DKIM CNAMEs, the return-path MX, SPF and DMARC. One missing, failed or mismatched record leaves the domain unverified. An empty record set is not verified.
A test key may send from any domain the tenant has added that is not deleted, including pending and failed. Those emails are accepted and discarded. They are not delivered.
An unknown domain, a deleted domain, or a domain that belongs to another tenant returns 404 not_found.
That response does not ask for DNS records.
How to fix
Add the DNS records returned for the domain, then call POST /domains/{domain_id}/verify.
A live key stays rejected until that check marks every record valid.
To send before verification, use a test key on a domain this tenant has added.
Source: docs/errors/domain_not_verified.md.