cannot launch node of type [occupancy/occupancy_node]: Cannot locate node of type [occupancy_node] in package [occupancy]

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I try to run this code: https://github.com/IntelRealSense/rea...

In my laptop using ros melodic and both realsense.

I run the code and it compiles ok.

When I run:

$ source devel/setup.bash
$ roslaunch occupancy occupancy_live_rviz.launch

Many errors appear, the first is:

ERROR: cannot launch node of type [occupancy/occupancy_node]: Cannot locate node of type [occupancy_node] in package [occupancy]. Make sure file exists in package path and permission is set to executable (chmod +x)

What can I do?