Hi,
apex 5.0 running on centOS 7.1, mail server is running on it locally and can send mail using mail -s.
Mail Queue showing ORA-29278:SMTP transient error:421 service not available in Apex admin, and can not send using a script.
I have tried using internal IP (127.0.0.1) and it's proper IP address in smtp_out_server, and in instance manager in apex admin with no joy.
I have also tried entering smtp authentication username, but still nothing.
Any help/ideas would be wonderful, as have looked through here but all point to service not running or permission problem connecting to remote server, but this is on same server.
Thanks