I am new to  Power Apps/Power BI. I have created 13 apps that feed into PowerBI.
 
I gave 4 staff members access to their apps, those 4 staff members have the following banner, "Error when retrieving data from network."
 
I have been working with one individual person on how to correct the issue. I have had them clear their cache. I have taken their data row limit from 2000 to 500, republished the app and had them attempt to use the new published app. 
 
Those 2 things have not worked. What are the other "fixes" to the issue?
 
Like I said I am new to power apps, any replies are appreciated with directions, thank you!