The self signed certificates are generated during the time of installation only.

Hence, in order to fix the issue follow the below steps:

Take snapshot of the connection server OR Adam DB backup

Uninstall the connection server application ONLY from Control Panel > Installed Program

Reboot the Connection server and reinstall the Connection server application again.

NOTE: DO NOT UNINSTALL OR REMOVE "AD LDS Instance VMwareVDMDS" 

During the time of reinstallation, the application will detect the existing AD LDS instance and use the same once continue. This will create a default cert again.