TCP connection
Can your client reach the SMTP host on the selected port?
SMTP test — verify connection, authentication, and TLS.
Confirm your SMTP hostname, port, username, and encryption settings before sending production mail. Use after configuring SMTPServer or any SMTP provider.
What does the SMTP test check?
TLS & auth
STARTTLS or implicit SSL negotiation and LOGIN/PLAIN authentication.
Ready to send
After a successful test, send a real message through the Mail Tester.