Dynamic Registration failing (or no action)

I'm working to setup a LTI provider and was testing the dynamic registration (which looked to be so simple!) based on the documentation at: https://docs.moodle.org/403/en/Publish_as_LTI_tool#Dynamic_Registration

1. Site administration > Plugins > Authentication > Manage authentication and enable LTI (complete)
   
2. Site administration > Plugins > Enrolments > Manage enrol plugins and enable 'Publish as LTI tool' (complete)