I have a Web page here: http://www.dimadayoub.net/forgot.aspx for users who have forgotten their password.

When I type in the email address of a user who I know exists as an entry in the MS Access database, I get the following

Mailbox unavailable. The server response was: Authentication is required for relay

There then follows a 12-line 'Stack Trace'.

I know that the SMTP credentials (Webmaster email, password, port number, and IP Address) are correct because my Web hosting service tells me so, and because those same credentials are used here:


If it is not the credentials, what else may be the problem, please?


If you want to be sure 100 percent, why not set a flag pending confirmation while sending an email to the user to confirm the address?