iSupplier Help - invitation did not send the emails out to the supplier user

Hello,

We are still in the implementation phase. We have set the isupplier portal and is in testing phase. I tried inviting a supplier user (from with the buyers facing responsibility ) with say an email id xyz@abc.com . I get a notification that an email was sent to this email address with a temprary pwd.

But the mail was not received on the email address. we restarted the wf mailer and it still did not work. there are no notifications generated in workflow page.

How and where can I check what went wrong. implementation/user guide doesnt provide any clue.