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.

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