When creating users within TDM Portal the following exception is received:
Failed messages: javax.mail.SendFailedException: Invalid Addresses; nested exception is: com.sun.mail.smtp.SMTPAddressFailedException: 554 5.7.1 <unknown[184.108.40.206]>: Client host rejected: Access denied
The SMTP error codes "554 5.7.1" generally note that the message was rejected by the SMTP server.
TDM Portal with an SMTP mail server configured.
Check the SMTP server configuration and ensure that it will allow messaged to be sent by the TDM Portal server. The TDM Portal server may need to white listed within the Access Control List.
See RFC6409 for SMTP Error code definitions.