Couldn't load the data for this visual

JackPo There could be number of reasons for this error. Several people have experienced it based on different scenarios. You need to start by looking at the special features / calculations / tricks used in your report. To give you example

If you're using RLS in your report and have used publish to web for that report you will get this error.

If you have used measures and calculation of that becomes invalid then you will see this error (the way you will handle that is by using IF else so if values of calculation becomes invalid  you handle that). 

Sometimes using multiple data sources results in this issue.

I would suggest you start by checking RLS, then if you have special measures / calculations and troubleshooting further from the information you get.

Hi JackPo,

I agree with @ankitpatira. This error could be caused by several issues.

By the way, could you please explain a bit regarding the “Very simple Power BI tool that uses gateway to access 5 excel sheets.”?

Where are those 5 Excel Sheets stored?

In addition to the suggestion to start the troubleshooting from RLS, please also follow the steps below:

1. Verify Power BI account, and the related permission settings;
2. Check the connectivity between your gateway and the Power BI service, we may follow the article below for a start:
3. (Personal Gateway, On-Premises Data Gateway)
4. Check your refresh settings, Data gateway settings and Data source settings under Power BI service;
5. If all good, re-publish the PBIX file.

Regards