Common Verification Errors and What They Mean

Here's a reference guide to the most common verification statuses and error conditions you may encounter.

Invalid Statuses

invalid_syntax

Meaning: The email address doesn't follow the correct format.

Examples: Missing @ symbol, spaces in the address, illegal characters, or the address is too long.

Action: Check for typos. This address cannot receive email.

invalid_domain

Meaning: The domain part of the email address doesn't exist in DNS.

Examples: user@nonexistentdomain.com, misspelled domains like user@gmial.com.

Action: Check for domain typos. Common mistakes include gmail → gmial, yahoo → yaho.

invalid_domain_no_mx

Meaning: The domain exists but has no MX records configured, meaning it cannot receive email.

Examples: Domains used only for websites, parked domains, or improperly configured domains.

Action: Remove this address — even if the domain is real, it can't receive email.

invalid (hard bounce)

Meaning: The mail server explicitly rejected the recipient. The mailbox does not exist.

SMTP codes: 550 ("User not found"), 553 ("Mailbox not available").

Action: Remove immediately. Never retry hard bounces.

Risky Statuses

risky_catch_all

Meaning: The domain accepts email for any address, so we can't confirm this specific mailbox.

Action: Keep if you have engagement data; treat cautiously for cold outreach.

risky_missing_spf / risky_missing_dmarc

Meaning: The domain lacks proper email authentication records.

Action: The address may still be deliverable, but the domain's security posture is weak.

Flags to Watch For

• Disposable email — A temporary/throwaway address (e.g., Mailinator, Guerrilla Mail). These are typically used to avoid giving a real email.
• Role-based address — Generic addresses like info@, admin@, support@. These often go to shared inboxes and have higher complaint rates.
• Free email provider — The address is at a consumer provider (Gmail, Yahoo, etc.) rather than a business domain.