Can't send SMTP mail with one of the mail servers using Windows Live Mail

 

Used to using Windows Live Mail to receive POP3 mail and send SMTP mail on couple of mail 
servers. 
Recently, can not send mail thru one of the mail server while receiving mail is still 
working fine.
Telnet the port 110 of this mail server is OK, but, can not telnet the port 25.
The other mail server is OK on both sending and receiving mail, so as the ports 25 and 110.
I wonder if Norton Internet Security 2010 stops me from sending mail thru this mail server.
Could not find the way to clear the blocking of port 25 for SMTP on this mail server.
Actually, don't know how to do anything on port, on SMTP and POP3 with firewall.

 

How to fix it?

David