SmtpFailedRecipientException: Mailbox unavailable

I am using asp.net password recovery page and its failing when comes to emailing.
this is the error I get : SmtpFailedRecipientException: Mailbox unavailable
this is my webconfig settings
<system.net>
<mailSettings>
<smtp from="[email protected]" >
<network host="smtp.xxxx.com" password="xxxxxx" userName="XXXX" defaultCredentials="false" />
</smtp>
</mailSettings>

Please help me with this.
The page is working fine locally but fails on discountasp.net server, its this web config page problem only because I am able to email from my application when I am using my own emailing code.
Thanks

 

Hi,
Try like this:
<system.net>
<mailSettings>
<smtp from="[email protected]" deliveryMethod="Network">
<network host="localhost" port="25" password="xxxxxx" userName="[email protected]" />
</smtp>
</mailSettings>
</system.net>

 

Thank you its working but how ??

Thank you , awesome it worked !!! but I have a question ...how is it working for "Localhost" when I am using a remote server smtp.xxxx.com
Thanks again
Pranay