Message not received

1. Confirm the recipient domain's MX record.
2. Confirm the mailbox exists and is active.
3. Check the sending system's SMTP result.
4. Check the JKMail SMTP logs.
5. Check spam-filter decisions.
6. Check final local mailbox delivery.

Authentication failure

Verify the complete mailbox identity, password, account status and connection security settings. Repeated failed logins can also trigger security controls.

Temporary 4xx response

A 4xx response represents a temporary SMTP failure. Inspect the exact response and server policy before assuming permanent rejection.

Mail stuck in queue

Review the destination MX, DNS resolution and destination-server response. The queue reason normally identifies whether the failure is network, DNS, policy or remote-server related.

Webmail login problem

Confirm that direct mailbox authentication works first. If authentication succeeds outside webmail, investigate the webmail configuration or connection path separately.

Support information

When escalating a mail issue, provide the sender, recipient, approximate timestamp and SMTP response or queue identifier where available. Do not publish passwords or private cryptographic keys.