Feedback for articles/insights-about-referrers.md

[benyrfg]

Is your feedback related to a problem? Please describe.
I created a dashboard for tracking referrers step by step by this article. But as a result is an error:
Error: The operation could not be completed. (DataTransferObjects.CustomQuery.QueryGenerationError error 2.): undefined

Describe the solution you'd like or the information you're missing
Sources chart

Additional context

[winsmith]

Thanks for reporting! I'll look into this