If you are using Outlook Express (OE), Outlook, or Windows Mail, A HELO error ( 550 Access denied - Invalid HELO name (See RFC2821 4.1.1.1) ) can sometimes be generated by leaving the "My server requires authentication" checkbox unchecked.
Use the below examples to find this "My server requires authentication" checkbox:
- Outlook 2000
Go to Tools > Services (or Tools > Accounts, if Services is not listed). Select your Internet E-Mail Account and click “Properties.” Go to the “Servers” tab, and check “My server requires authentication” under Outgoing Mail Server. Click “Settings,” select “Use same settings as my incoming mail server,” then click “OK” three times to save the changes & return to Outlook. Finally, restart your computer.
- Outlook 2002 & 2003
Go to Tools > E-Mail Accounts. Select “View or change existing e-mail accounts” and click “Next.” Select your email account and click “Change.” Click “More Settings.” Go to the “Outgoing Server” tab, and check “My outgoing server (SMTP) requires authentication.” Select “Use same settings as my incoming mail server” and click “OK.” Click “Next,” then click “Finish” to confirm your changes and return to Outlook. Finally, restart your computer.
- Outlook Express
Go to Tools > Accounts. Select the “Mail” tab. Select your email account and click “Properties.” Go to the “Servers” tab, and check “My server requires authentication” under Outgoing Mail Server. Click “Settings,” select “Use same settings as my incoming mail server,” then click “OK” twice times to save the changes, then click “Close” to return to Outlook Express. Finally, restart your computer.
- Outlook 2010 or higher
Go to File > Account Settings. Select the email account you are are having issues with and click “Change” and click “Change.” Click on “More Settings.” Go to the “Outgoing Server” tab, and check “My outgoing server (SMTP) requires authentication.” Select “Use same settings as my incoming mail server” and click “OK.” click “Next,” then click “Finish” to confirm your changes and return to Outlook. Go to File > Exit, restart your computer.
As of Oct 28th 2013 -- We now require all of our hosting clients to use this method when connecting to our SMTP server. The old "pop before sending" method is no longer supported. If you enable SMTP authentication and you are still having sending problems, then please fill out a support ticket via your client area.
