3 answers
FWIW and for anyone else who finds this via search: I was logging into my playground org via my credentials and not by hitting the launch button at the bottom of the Trailhead Unit.
To resolve this error, I logged out of the playground org, and then hit the "Launch" button at the bottom of the unit page. I noticed the the report didn't seem to be there, so I created it again and clicked the "Check Challenge..." button. Error resolved.
