Hi Ali Khoshbin,
>>Do you know what steps should I take to enable email notification of SQL in exchange 2007 ?
Regarding to your description, which seems be an Exchange issue.
According to how To Set Up SQL Mail With Exchange, please refer to this KB:
INF: How to Configure SQL Mail.
Here is a
Blog is related to Sending Automated Job Email Notifications in SQL Server with SMTP.
Meanwhile please refer to this
KB about the SQL Server Agent Job with E-Mail Notification Option Stops Responding When Microsoft Exchange Server is Not Available.
Additional, please link to
Exchange forum, you can get better help.
Regards, Amber zhang