What are the possible states and reasons for verification results?

Deliverable

• Accepted Email: Email is deliverable

Undeliverable

• Invalid Email: Specified email is not a valid email address syntax
• Invalid Domain: Domain for email does not exist
• Rejected Email: Email address was rejected by the SMTP server, email address does not exist
• Invalid SMTP: SMTP server returned an unexpected/invalid response

Risky

• Low Quality: Email address has quality issues that may make it a risky or low-value address
• Low Deliverability: Email address appears to be deliverable, but deliverability cannot be guaranteed

Unknown

• No Connect: Could not connect to SMTP server
• Timeout: SMTP session timed out or DNS query timed out
• Unavailable SMTP: SMTP server was unavailable to process our request
• Unexpected Error: An unexpected error occurred