Opening web page link on EP opens different page

Dear Portal Gurus,

In the Intranet, if we send an auto generated email alert to a user, we can embed a link which user can click, open the web page and complete the action required from his end and close the link.

However, if we do the same thing for email generated by SAP with a link for a web page on the SAP Portal, and a user clicks on the link then sometimes one default page is displayed. It does not open the page directed by the link.

How do we resolve this?

Thanks in advance

M