javax.mail.MessagingException: Could not connect to SMTP host in ODI sentmail

1. Check if the SMTP server is working by trying to connect from server where the Weblogic Server is running to the server where is the SMTP mail server is installed and send an mail.

Here are steps to check:

bash-2.05$ telnet <your mail server> 25
Trying 127.0.0.1...
Connected to server.
Escape character is '^]'.
220 server ESMTP Exim 3.35 #1 Wed, 07 May 2003 11:27:45 +0100


HELO eMonster
250 server Hello emonster [127.0.0.1]

MAIL From:<Sender email address>
250 <your email address> is syntactically correct

RCPT To:<Receiver email address>
250 <Receiver email address> is syntactically correct

DATA
354 Enter message, ending with "." on a line by itself
This is a test email

From,
Enter some text ....
.
250 OK id=19DMAH-0003tv-00
^]
telnet> quit
Connection to server closed.
bash-2.05$

2. You need to set a host name and IP Address in /etc/hosts.
3. You need to check if a server port  is correct.
4. Current server and port values you can find in oms-config.xml.

Reference: Cannot Send Email: Javax.mail.MessagingException: Could Not Connect To SMTP Host (Doc ID 1280242.1)