When you try to access the default database:http://localhost:9090/denodo-restfulws/admin it will prompt you for the login credentials.Please ensure that the username and password are correct.
Please ensure the following
* Check that there is no other application running in the 9090 port.
* Enusre that the base view "client" exists in the database.
If this still doesn’t work you can check the tomcat logs where you may find more useful information: <DENODO_HOME>/logs/apache-tomcat.
Hope this helps!