Hi, we are  developing a web based mailclient where we are having more that 3 Laks User . We are Authenticate User from Active Directory. But our main problem is that we are getting Server is not operational Error very Frequently. We have a searching Functionality wher we need to search data from AD also, for that we are hiting AD .

Now my Question is . How can I reselove this problem ?  Is this error related to huge number of connection with AD ? But we are dispoing the object also. Or is there any better approch to Create DictonaryEntry Object and using AD for huge number of user ? or This is any different Reseon.

One more point: Our Development Domain  and MailClient Domain is Different . but we are getting same problem while testing the product from same domain.

I have Search Google !!! but Till now no solluation .

Any Idea !!!

Thansk in Advance !!!!

You should probably start by looking at your domain controller(s). 

Start with this article: http://www.microsoft.com/technet/solutionaccelerators/wssra/raguide/DirectoryServices/igdrbg_4.mspx

Do you have > 1 DC?  Have you got load-balancers in place if you have?