Learn how to deal with Power Query Error: Formula.Firewall: Query references other queries or steps, so it may not directly access a data source. Please rebuild this data combination. Two solutions are presented in this video.
Download Files: Excel Start: https://people.highline.edu/mgirvin/AllClasses/348/MSPTDA/Content/PowerQuery/009-MSPTDA-ValuesExpressionsFunctions-Start.xlsx
Zipped Folder: https://people.highline.edu/mgirvin/AllClasses/348/MSPTDA/Content/PowerQuery/009-ParameterQueryTables.zip
Download Excel FINISHED Files: https://people.highline.edu/mgirvin/AllClasses/348/MSPTDA/Content/PowerQuery/009-MSPTDA-ValuesExpressionsFunctions-Finished.xlsx
Download pdf Notes about Power Query: https://people.highline.edu/mgirvin/AllClasses/348/MSPTDA/Content/PowerQuery/009-MSPTDA-ValuesExpressionsFunctions.pdf
Assigned Homework - these are problems for you to practice your new M Code skills:
Download Excel File with Homework: https://people.highline.edu/mgirvin/AllClasses/348/MSPTDA/Content/PowerQuery/009-MSPTDA-Homework-Start.xlsx
Example of Finished Homework: https://people.highline.edu/mgirvin/AllClasses/348/MSPTDA/Content/PowerQuery/009-MSPTDA-Homework-Finished.xlsx

Chris Webb’s blog about this topic: https://blog.crossjoin.co.uk/2017/06/26/data-privacy-settings-in-power-bipower-query-part-3-the-formula-firewall-error/):
Ken Puls blog about this topic: https://www.excelguru.ca/blog/2015/03/11/power-query-errors-please-rebuild-this-data-combination/

Comprehensive Microsoft Power Tools for Data Analysis Class, BI 348, taught by Mike Girvin, Excel MVP and Highline College Professor.