5- Understanding ROS Services-Clients: Getting error while solving exercise 3.1

Even though I have included <include file="$(find trajectory_by_name)/launch/start_service.launch" /> in the launch file, I am getting the following error:

But when I start the service in a separate terminal (Without starting it by including it in the launch file) and then call the service, the project works perfectly.

That might be a sourcing problem. Try compiling your project again and sourcing with

cd catkin_ws/
rm -rf build/ devel/
source devel/setup.bash
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