[SocketException (0x274d): No connection target machine actively refused it.

[uzunhac]

Dear All,
I am having a strange problem with ASP Mail Sending.
I am receving
[SocketException (0x274d): No connection could be made because the target machine actively refused it]
[WebException: Unable to connect to the remote server]
[SmtpException: Failure sending mail.]

I have google a lot but nothing matching.

Facts:
Framework 2.0
<authentication mode="Forms">
It is working from my development machine.
I Have developed another console application(CAPP) for testing.

On Production
Telnet Mailserver 25 is working.
CAPP is working when I run it from command line.
CAPP is NOT working when I try to schedule it as as scheduled task.
Web app is NOT working within ASP.NET applcation.

What I have tried:
I have tried adding following attribute combinations to mail sending method.
<Net.SocketPermission(System.Security.Permissions.SecurityAction.Demand)> _
Above does not generate compile errors but result is failure.
<Net.SocketPermission(System.Security.Permissions.SecurityAction.Demand, , , , , True)> _
Above is giving compile error
Too many arguments to 'Public Sub New(action As System.Security.Permissions.SecurityAction)'.
According to method help, last parameter is Unrestricted which I try to set

I Have included ASPNET, IWAM..., IUSR... Users to Administrators groups

Any help?
Thanks in advance.