Some Internet Service Providers (ISP’s) will block sending mail on the default port 25. Follow the Steps Below to take you through changing your port to 587 which will allow mail to be sent.
1. Start Microsoft Outlook Express, select Tools » Accounts.
2. Select the Mail Tab, Highlight the account you want to change the outgoing port for and click Properties.
3. Select the Advanced Tab, Change the Out Going Server Port to 587 and click OK
4. Click Close.
NB. You should now be able to send mail via our outgoing mail server without being blocked by your ISP.