How to enable SMTP Authentication
Generally if you are using a mail server apart from your ISP’s one, such as your web host, then you will need to enable SMTP Authentication on it to be able to send outgoing mail. When you try to send mail this will authenticate with the outgoing mail server, giving them your username and password for your email hosting that you are authorized to send mail from. Most servers will not accept mail if you do not authenticate with them, a server not requiring this would be a spammer’s dream and this mail server would soon get blacklisted by spam databases.
Here is how to enable SMTP Authentication in some common email clients:
Microsoft Outlook Express
- Select Tools and then Accounts.
- Click the Mail tab.
- Select the account you want to to enable authentication on and choose Properties.
- Click the Servers tab.
- Select the “Outgoing Server” Tab
- Tick “My server requires authentication”.
- Click the Settings button.
- Ensure you also select the “Use same settings as my incoming mail server” option.
- Choose Apply.
- Choose Close.
- Choose Close.
Microsoft Outlook XP and 2003
- Select Tools and then Email Accounts
- Highlight View or change existing e-mail accounts then Choose Next.
- Select the account you want to to enable authentication on and choose Change.
- Choose More Settings.
- Select the Outgoing Server Tab
- Tick My outgoing server requires authentication.
- Ensure you also select the Use same settings as my incoming mail server option.
- Choose OK.
- Choose Next.
- Choose Finish.
Mac Mail Client OSX 10.4 upwards
- Choose the Mail menu and click Preferences.
- Choose the Accounts tab
- Click the arrow box on the Outgoing Mail Server (SMTP) pop-up list and choose Add Server.
- In the Outgoing Mail Server field enter your SMTP mail server address.
- Select the check box on the Authentication list and choose Password.
- In the User Name field, enter your full email address or username.
- In the Password field, enter your e-mail password.
- Click OK.
Some possible errors you may encounter if SMTP Authentication is not enabled are:
550 rejected RCPT – your.hostname.com [184.108.40.206] is currently not permitted to relay through this server. Perhaps you have not logged into the pop/imap server in the last 30 minutes or do not have SMTP Authentication turned on in your email client. 250 Reset OK
503 valid RCPT command must precede DATA
JunkMail rejected – your.hostname.com (hostname) [220.127.116.11] is in an RBL, see https://www.spamhaus.org/query/bl?ip=18.104.22.168 – This error is caused by the IP being in the Policy Block List (PBL), an example is here: https://www.spamhaus.org/pbl/query/PBL174229 . This occurs because the client does not use SMTP Authentication.