Alert mails are not coming after the initial alert created mail

[sravi]

I have configured the alert options to receive an email when a new document is added or modified in the site which i have added using sharepoint.

When any user sets up the alerts, an email is received stating that the alerts has been created. Example:

Alert 'Tasks' has successfully been added on 'CTSC'.
You will receive alerts in e-mail. The timing and criteria for the
alerts depend on the settings entered when the alert was added.
You can change this alert or any of your other alerts on the My Alerts
on this Site page.

After this mail, no one gets any email notification about new document added or modified.

the IP address of the SMTP server is correct, configured the Outbound email settings correctly in the SharePoint Central Administration and also the Applications Managements area with the correct Outbound email settings.


Please help...