Resolution:
TEA by default uses $TEA_JAVA_HOME/lib/security/cacerts trust store. Users can import the LDAP server certificate to this keystore and restart the TEA server.
Alternatively, users can create a new keystore file, import the LDAP server certificate and add the following properties in the tea.tra file. Restart the server, then add the LDAP realm again.
java.property.javax.net.ssl.trustStore=<path/to/truststrorefile>
java.property.javax.net.ssl.trustStorePassword=<trustStorepassword>