Issue
The Mail Service in a Niagara R2 UNC station is configured correctly, but MailRecipients do not receive emails. The following error appears in the Standard Output Window:
javax.mail.SendFailedException: Sending failed;
nested exception is:
javax.mail.SendFailedException: Invalid Addresses;
nested exception is:
javax.mail.SendFailedException: 550 5.7.1 Unable to relay
Debug logs show:
DEBUG SMTP RCVD: 550 5.7.1 Unable to relay
DEBUG SMTPTransport: Sending failed because of invalid destination addressesProduct Line
TAC IA SeriesEnvironment
Niagara R2
Cause
The SMTP server is not configured to relay emails to external addresses. If the recipient email account does not exist on the SMTP server, the message cannot be forwarded.
Additionally, if multiple addresses are configured and any one address fails, none of the emails will be sent.
Additionally, if multiple addresses are configured and any one address fails, none of the emails will be sent.
Resolution
-
Verify the SMTP server settings:
- Ensure it is configured to relay emails outside its own domain.
- Contact the site’s IT department to enable SMTP relay for external addresses.
-
Validate recipient addresses:
- Remove invalid or non-relayable addresses from the MailRecipient configuration.
-
Test sending an email to a valid account on the SMTP server to confirm connectivity.
