Connecting To xxx.xxx.xxx.xxx...Could not open connection to the host, on port 25: Connect failed.

Many people have that problem. It may be caused by several reasons: firewall, antivirus, security policy of ISP, etc. In my case, it was antivirus software which blocked 25 port.

Steps to identify problem.

1. Telnet host on 25 port. See http://technet.microsoft.com/en-us/library/bb123686.aspx for details.

2. Try to turn off firewall.

3. Try to turn off antivirus. Worked for me! Add the process and / or port to exceptions.