As described in the title, I was not able to run the Lesson 6 Lab, exercise 1 (Instrumentation of the Python (Flask) Component (1)).
The reason seems to be that a system process already takes the default port 5000.
Workaround: change the port to anything not used yet.
Changes I made to file automatic-instrumentation/todoui-flask/app.py:
# ...
if __name__ == '__main__':
app.run(host='0.0.0.0', port=5002)
# app.run(debug=True) # doesn't work with auto instrumentation