I've been dealing with the "Formula.Firewall" issue for a long time. Since I didn't need to use the scheduled refresh feature of the Power BI service, I would disable the privacy checking. But now I need to use the scheduled refresh feature for some of my most complex data models. I've gone through and added "staging" queries to address a number of the Formula.Firewall errors, but now I'm running into a weird situation.
In a nutshell, I can resolve the Formula.Firewall errors I'm seeing without actually changing any of the queries. First, I click "Refresh" in Power BI Desktop to update all tables, and I'll quickly get the Formula.Firewall error for a table. I then go into the queries editor and visit the table that's giving me the problem. I see the error and then start to visit the tables that are being merged into this query. For many of these dependent tables, I see the "Unexpected error: Evaluation was canceled" message and I click retry. If I do that for all the dependencies, I eventually get back to the main table that was giving me the error and the error magically goes away!
If I go back to the main Power BI Desktop screen, I need to click Refresh again because none of the queries have actually changed -- I've just refreshed them in the query editor. I will then see the Formula.Firewall error for another table and I'll have to repeat the process I described above. This takes a really long time and I have to do it every time that I refresh the data model.
I can't explain why I'm getting these errors or why my workaround resolves them. I'd greatly appreciate help from someone on what's going on here and how I can fix it once and for all.
