The most common reasons for IRWebHost customers to be unable to send emails through Outlook Express are wrong Outlook settings or blocked port 25 by the Internet Service Provider.
Use the correct Mail Client settings:
* Incoming mail server (POP3/IMAP server): mail.yourdomain.com (where you'll replace yourdomain.com by your own)
* Outgoing mail server (SMTP server): mail.yourdomain.com (where you'll replace yourdomain.com by your own)
* Username: the full e-mail address like firstname.lastname@example.org
* SMTP authentication must be enabled for the login to be successful.
IMPORTANT: Please do not use secure authentication to your mail server.
The most common mistake is to leave My SMTP server requires authentication checkbox unchecked. This option should always be enabled, since IRWebHost servers require such authentication. Please find below how to enable the SMTP authentication for your Outlook express mail client:
From the Tools menu select Accounts. The Internet Accounts box appears. Select the Mail tab. Your email account appears. Select the appropriate email account by clicking on its name and click the Properties button on the right. Then under the Outgoing Mail Server section check the box My server requires authentication. Do NOT check the box next to Log on using Secure Password Authentication.
Check connection to port 25
The standard port usually used for SMTP connection is port 25. Most often the reason for failed email sending is that your Internet service provider blocks this port. If is the case we recommend that you use the alternative port 26 for your email SMTP connection.
For detailed instruction how to check you connection to port 25 with the most popular OS and how to change your default SMTP port to 26 please refer to the SMTP refuses connection article.