In 2.3.4 Ranger Hive Repo Test Connection not working with HS2 HTTP TransportMode configuration.
Workaround:
1) Move httpclient-4.2.5.jar httpcore-4.2.5.jar from /usr/hdp/current/ranger-admin/ews/webapp/WEB-INF/lib to a tmp folder.
2) fetch the httpclient-4.4.jar and httpcore-4.4.jar from /usr/hdp/current/hive-server2/lib/ and place it in /usr/hdp/current/ranger-admin/ews/webapp/WEB-INF/lib folder
3) Restart ranger admin and configure hive repo with http config and test the HTTP connection and lookup.