OCS 2007. I have added the SIP for 1 user and when i try to connect it does not connect the client. Is there any other thing we need to set.

have you configured the certificate correctly, what does the error says

Certificate is installed.
I get this
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Office Communicator
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Cannot sign in to Communicator. You may have entered your sign-in address, user name, or password incorrectly, or the authentication service may be incompatible with this version of the program. If your sign-in information is correct and the problem persists, please contact your system administrator.
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OK  
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try to install the OCS 2007 R2 client instead, also make sure that you have the DNS entries created and configured correctly.

I have OCS 2007 R2 installed
DNS where should i check for it

which version of OCS 2007 R2 you are using, standard or enterprise?
and how did you configure the OCS client to login, do you enter the server name or use automatic configuration.
please check my dns and certficiate calculator it will helo you to configure certificate and DNS:
http://busbar.blogspot.com/2010/03/dns-and-certificate-calculator-for.html

Standard
I enter the server name

ok when you enabled the user for SIP, which email address did you use, and did you add this SIP domain to the OCS?

It took the remote domain email address . yes its added

Thank U

so which one helped you, the KB or there was mis configuration for user properties.

In AD i had to enable the SIp then run the Script nd it worked

perfect it was nice to know that I helped