Error codes
Stable error codes for clients. HTTP status is separate from the machine code.
Codes
invalid_domain, wildcard_requires_dns, domain_not_verified, provider_unavailable, ca_rate_limited, dns_record_not_found, dns_propagation_timeout, acme_validation_failed, certificate_order_failed, certificate_not_renewable, certificate_already_revoked, insufficient_scope, idempotency_conflict, quota_exceeded.