Unable to send mail through port 25

[Nereus]

I am facing the problem in sending emails through the port 25. I am having problem with some application which send the emails using the exchange 2007 sp1server. The error message which i am getting is that the "421 4.3.2 Service not available, closing transmission channel". So if anyone knows about this issue and solution then do reply over here.

[Sabastiaan]

You are having problem in sending the emails from the port 25 using the exchange 2007 sp1server. You are getting some error code which shows Service not available, closing transmission channel. So may be you are not properly connected to the internet or may be there is some connection error with the Port 25 which is causing this issue. So check out for this possible error.

[Visala28]

It is possible that your Internet service provider has blocked the mail server which you are using for sending and receiving the emails. You are using the exchange 2007 sp1server for sending the mails to the others. So i think you should contact to your internet service provider for the same. Only they can resolve this issue properly.

[teenQ]

If am sure that your Internet service provider has bloked you from sending the mails trough the SMTP server. So dont worry there is a solution for this issue. You can use the port 26 instead of the port 26 for sending mails. You can do this by mentioning the your mail client to use port 26. This is the alternative solution for the port blocking issues.

[Candace]

It is possible that the firewall of your computer system is blocking you from sending the mails using the port 25. So i will advise you that first you should disable the firewall of your computer system and try sending the mail using the same mail server and the port 25. I think this will fix the email sending issue from the SMTP port 25.