IIS 5 & IIS 6
IIS SMTP not sending mails on Hmailserver
Last post Sep 17, 2012 04:53 AM by necro_mancer
Sep 16, 2012 08:36 AM|shaikhtaufik|LINK
Sep 16, 2012 07:35 PM|JamieFurr|LINK
Is the mail server accepting connections? You can verify this using the Telnet client. Type the following command at the command line.
telnet mailserver.domain.com 25
If it makes a connection then your mail server is listening. You may want to test this from the mail server locally and also remotely from another machine.
You can test around your ASP.NET application by connecting with a mail client such as Outlook or by testing with telnet session.
Here's a good article on how to test an SMTP server with telnet:
Sep 17, 2012 04:53 AM|necro_mancer|LINK
the error message is quite clear. Your SMTP port 25 is blocked and you need to find a way to unblock it.
Also, you need to make sure you configure Reverse DNS for your domain name