How to change the outgoing mail (SMTP) port

If you can't send email (but you can receive, in some cases), your ISP, firewall/antivirus software, or your router may be blocking the default outgoing mail (SMTP) port, which is 25. This is the standard port for sending mail, but it is often blocked because spammers commonly use this port.

The problem can often be resolved by changing your SMTP port number to 587. Here are instructions Instructions on how to change the outgoing mail port in Microsoft Outlook, Outlook Express, Mozilla Thunderbird, Mac Mail, Entourage, and Eudora:

Outlook 2003

  • On the menu bar, select "Tools" and go to "E-mail Accounts".
  • In the "E-mail Accounts" wizard window, select "View or change existing e-mail accounts" and click "Next".
  • Click the "Mail" tab and choose the account you need to modify.
  • Click "More Settings".
  • Click the "Advanced" tab.
  • Change "Outgoing server (SMTP)" port from 25 to 587.
  • Click "OK".
  • Click "Next".
  • Click "Finish".

Outlook 2007

  • On the menu bar, open "Tools" and go to "Accounts Settings".
  • In the "E-mail Accounts Settings" window select your domain's email account.
  • Click the "Change..." icon.
  • Click "More Settings".
  • Click the "Advanced" tab.
  • Change "Outgoing server (SMTP)" port from 25 to 587.
  • Click "OK".
  • Click "Next".
  • Click "Finish".

Outlook 2010

  • Click the "File" tab, then click the "Account Settings" button.
  • Highlight the account you want to change, then click "Change" to open the settings window.
  • Click the "More Settings" button, then choose the "Outgoing Server" tab.
  • Check that "My outgoing server (SMTP) requires authentication" is chosen. If it is not, click the box.
  • Check that "Use same settings as my incoming mail server" is chosen. If it is not, click the box.
  • Choose the "Advanced" tab.
  • Change "Outgoing server (SMTP)" port from 25 to 587.
  • Click "OK".
  • Click "Next".
  • Click "Finish".

Outlook Express

  • On the menu bar, click "Tools" and go to "Accounts".
  • Click the "Mail" tab.
  • Select your domain's email account from the list. Click the "Properties" button.
  • Make sure that the "Include this account when receiving mail or synchronizing" box is checked. If it is not, check it.
  • Click the "Servers" tab. Locate the "Settings" button below "Outgoing Mail Server". Click the "Settings" button.
  • Locate the "SMTP Port" field (it should say 25). Change it from 25 to 587.
  • Make sure the "My SMTP server requires authentication" box is checked. If it is not, check it.
  • Click "OK". Click "OK" again until you've closed all the windows.
  • Restart Outlook Express.

Thunderbird

  • On the menu bar, click "Tools" and go to "Account Settings".
  • Select "Outgoing Server (SMTP)" on the left pane of the "Account Settings" window.
  • Select the SMTP server for your domain. Click "Edit".
  • Change the number in the "Port" field from 25 to 587.
  • Click "OK".
  • Click "OK" again to close the "Account Settings" window.

Mac Mail

  • Open "Preferences" in the "Mail" menu.
  • Click the "Accounts" tab to locate your domain's email account. Open it.
  • Open the "Outgoing Mail Server" window.
  • Change the number in the "Port" field to 587.
  • Check the "Use Authentication" box.
  • Click "Continue".
  • Click "Continue" again. Close any remaining open windows.

Entourage

  • Click "Tools", then "Accounts" from the menu bar.
  • Highlight the e-mail account you wish to change, then click Edit.
  • In the "Sending Mail" Section, click on the "Click here for advanced sending options" button.
Change the default SMTP port and authentication settings:
  • Make sure the "Override default SMTP port" option is chosen.
  • If Outgoing mail (SMTP) is 25, change it to 587. (If the port number is already 587, or another number like 465, do not change it.)
  • Make sure that "SMTP server requires authentication" is checked.
  • The option for "Use same settings as my receiving mail server" must also be checked.
  • Click the small square in the top-left of the "Advanced Sending Options" window to close it.
  • Click "OK" to close the main "Edit Account" window.

Eudora

To change the outgoing mail port to 26:
  • Click the "Tools" menu, then click "Options".
  • Scroll down, then click "Ports".
  • In the SMTP Port (25): box, type 587.
  • Click "OK".
  • Restart Eudora.
To enable SMTP authentication:
  • Click the "Tools" menu, then click "Options".
  • Scroll down, then click "Sending Mail".
  • Check the box next to "Allow Authentication".
  • Click "OK".
  • Restart Eudora.

Article ID: 1118, Created On: 3/28/2013, Modified: 6/30/2013