Sendemail the software in your host abandons an established connection.

From Network

If you have installed anti-virus software, for example, McAfee VirusScan.
They are blocked by default.ProgramSending emails, even web programs, will also block. I have encountered this anti-virus software to block Windows programs. Today, I found that web programs are also blocked.

When you send an email using a program, you may receive "unable to connect to the remote server", and "the software in your host has abandoned an established connection. "Exception.

To solve this problem, let the anti-virus software discard the restrictions on this program. Taking McAfee VirusScan as an example, you need to put your program name in the exception list. For example:
 
If our web program runs in Asp.net development server that comes with vs2005, the exception here is: webdev. webserver. EXE.

If it is in IIS 6, it is generally w3wp.exe.

IIS 5 is usually aspnet_wp.exe (XP)