Free Busy lookups from Lotus Notes to Exchange was not completing. The following error appears in the event log for the CMN Free Busy Connector:
"The request failed. The Underlying connection was closed. Could not establish a trust relationship for the SSL/TLS Secure channel."
This issue was caused by an incorrectly installed certificate on the Exchange server.
The issue can be resolved by removing the existing "faulty" certificate. Creating a New certificate, Installing the new Exchange certificate and replacing the Root certificate.
