I am applying a voxel filter to a point cloud stream but the topic is not being published and I cannot visualise the added pointclouds. rostopic echo /voxel_grid/kinect_test outputs:

WARNING: no messages received and simulated time is active.
Is /clock being published?

The output of rostopic info /voxel_grid/kinect_test is:

Type: sensor_msgs/PointCloud2

Publishers: 
 * /voxel_grid (http://toshiba:55381/)

Subscribers: 
 * /rqt_gui_cpp_node_2830 (http://toshiba:59223/)
 * /rqt_gui_py_node_2830 (http://toshiba:34321/)