To set up Microsoft Outlook Express:
Open Microsoft Outlook Express
Go to Tools > Accounts
Click the Mail tab to open a list of your mail accounts
Double click the account that has the problem
Click the Advanced tab
Change "Outgoing mail (SMTP)" from 25 to 26
Click OK and Close
You should be able to send mail
To set up Mozilla Thunderbird:
Open Mozilla Thunderbird.
Go to Tools > Account Settings
In the list on the left, select "Outgoing Server (SMTP)" at the bottom of the list Select the account you need to change from the list on the right and click Edit
Change Port from 25 to 26
Click OK and OK
You should be able to send mail
To set up in Outlook 2003 In Microsoft Outlook,
select Tools > E-mail Accounts On 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)" from 25 to 26
Click OK, Next, and Finish