After replacing a certificate for Live Communications Server 2005 (LCS), I replaced the certificate in the properties of the server. After starting the service, I noticed it stopped again and the following error was logged :

Event Type: Error
Event Source: Live Communications Server Protocol Stack
Event Category: (1001)
Event ID: 14397
Description:
A configured certificate could not be loaded from store. The serial number is attached for reference.

Extended Error Code: 0×800B0101.
Cause: This could happen if the certificate is not found. This could also happen if the server has insufficient privileges to read the certificate or to access the store containing the certificate.

I first thought this was an issue I had seen before, regarding private key and certificates. This didn’t solve the issue for me. Then I noticed the following. When you have a certificate for LCS, you need to select the correct certificate on 2 places! This is a bit confusing, but at least the problem got solved.

1. Open the LCS Management Console
2. Select the properties of the server
3. You have 3 tabs (General, Security and Logging)
4. On the General tab :
   Locate Connections, select the port (probably 5061, Mutual TLS) and select Edit
   Here you can add the correct certificate
5. On the Security tab :
   Select the same certificate