Please need to check the below step:-
you can do a manual check from the machine where you're running the emailgtw probe, using telnet <your_mail_server> 25.
Telnet to port 25 to test SMTP communication
NOTE: Press ENTER after you type each line.
1. Start a Telnet session by using the following command:
telnet <mail_server> 25
You will receive a response similar to this:
220 <hostname> -- Server ESMTP <(Sun Java System Messaging Server 6.2> -6.01 (built Apr 3 2006))
2. Begin communication by typing the following command:
HELO
You receive the following response:
250 <hostname> Hello [ip_address] , Pleased to meet you
Type the following command to tell the Gateway whom the message is from:
MAIL FROM:<
[email protected]>
You receive the following response:
250 Requested mail action okay, completed
3. Type the following command to tell the DMS whom the message is to (use a valid Microsoft Exchange recipient's SMTP address).
RCPT TO:<
[email protected]>
You receive the following response:
250 Requested mail action okay, completed
4. Type the following command to tell the GATEWAY that you are ready to send data:
DATA
You receive the following response:
354 Start mail input; end with <CRLF>.<CRLF>
5. Type the following command to add a subject line:
Subject: test message
Press ENTER two times. You will not see a response from this command.
6. Type the following command to add a message body text:
This is a test message.
You will not see a response from this command.
7. Type a period at the next blank line, and then press the ENTER key.
You receive the following response if its successful:
250 Requested mail action okay, completed
8. Close the connection by typing the following command:
QUIT