Hello,

The technical persons in our company have been trying to determine a problem that started occuring AFTER the sucessful deployment of LCS 2005.

Here is some environment information:
LCS 2005 Version 2.0.5470.0
Client Used: ONLY Microsoft Office Communicator 2005
Clients are located: Internal LAN clients only.
Approximate number of users: 350
Certificates: Not used
Authentication: NTLM or Kerberos

Problem:
Clients were connecting just fine for about a month, then users were randomly experiencing connection problems where they would try to connect using Office Communicator 2005 and the error "Cannot sign in to Communications Service because the server is temporarily unavailable. Please try again later. Retry/cancel. The user can retry and it may take many tries but it will connect successfully. Alternatively, the client might connect on first try.

We have investigated the following:
-DNS issues - none found
-LAN issues - none found
-Firewall issues - None, there is no firewall on, including Windows Firewall
-Using NTLM auth only - still had issue
-Using Kerberos auth only - Still had issue
-Correct permissions to SQL Database

With trace logs on, we are focusing on the only error we can see which is the following lines found when the client fails to connect:
-11:14:58.074 E8:1644 ERROR :: ASYNC_SOCKET::OnConnectReady - Error: 10061 dest: 10.100.225.34:5060
-11:14:58.074 E8:1644 ERROR :: OUTGOING_TRANSACTION::OnRequestSocketConnectComplete - connection failed error 80ee0067

I've googled that error and that's how i found this forum. The link to http://www.lcs-guides.com/cant-sign-sip-service-unavailable
came up, and that person's solution was to ensure the LCS accounts have proper DB access. I have the exact error as him, but for me it's intermittent, and my DB access is not the issue.

Using a netstat application i can see MANY connections to 5060. Is there a limit on the amount of connections a Windows server can have? btw, the hardware specs of our OCS box are way beyond what we need.

Any help is greatly appreciated. I'm looking for reasons as to why my local clients are having intermittent success when logging on to LCS 2005.