sql db mail problem while sending in bulk

I am using db mail(sql server 2005) to send bulk email(>2000). The code tat i use is,

exec msdb..sp_send_dbmail           
  @profile_name = 'My Profile',     
  @recipients = 'raghav.cinch@gmail.com',             
  @subject = 'test',          
  @body = 'test',          
  @body_format = 'HTML'

If i send few emails(less than 100), all emails are sent successfully. But only bulk emails give me error.

The error I get is,

The mail could not be sent to the recipients because of the mail server failure.         (Sending Mail using Account 8 (2011-09-27T21:29:17). Exception Message: Cannot send mails to     mail server. (Unable to send to all recipients.).
)

The error comes after 100 or 105 mails. The email addresses are correct and if i sent in cycles of 100, all mails are sent successfully.

I believe it should be some configuration settings tat ne开发者_如何学Goed to be tweaked. Could someone pls help me in fixing it..

Thanks in advance.

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Changed the iis6 settings, max queue length for the smtp server and this worked like charm.