The first thing I would check is to make sure the server administrator (or whomever is changing the port settings on the server) is actually restarting Virtual DataPort Server after changing the configuration. If they do not, then even if the *Server configuration* screen is showing 1111, the server is still *running* on 9999 until it is restarted. You can attempt a connection on 9999 to validate this.
Assuming that's correct, you can take a look at the *DENODO_HOME/logs/vdp-admin/vdp-admin.log* on your workstation to get some detail on the error shown when you attempt to log in using port 1111. If necessary, take a look at the documentation on changing the level of detail captured by the [Logging Engine](https://community.denodo.com/docs/html/browse/6.0/vdp/administration/appendix/configuring_the_logging_engine/configuring_the_logging_engine).
You shouldn't need to change the port anywhere else. In fact, the VDBAdminConfiguration.properties file *vdbDataSource.vdpAdminDataSource.vdbURI* property only controls the default you see when you launch AdminTool - this gets updated automatically based on what you set in the UI and shouldn't need to be changed manually.
Hope this helps!