We had some issues with running the perception part of the workshop and for most people running the command ros2 action send_goal /find_objects grasping_msgs/action/FindGraspableObjects "{plan_grasps: false}" we ended up with an abort.
The clue was in the perception1 window where it generated an error message saying camera timed out.
Because the open workshop resources are not as high as a production environment, I found I could tweak the timeout and get it to work.
In the file basic_grasping_perception.cpp under simple_grasping packageon line 226 I changed the timeout from 3 seconds to 10
if (clock_->now() - t > rclcpp::Duration::from_seconds(10.0)) which gave theconstructsim enough time to get the camera action response and not time out.
Just in case this helps anyone else 
All the best
Brian