Error viewing data in a data source

Symptom

When you open a data source in the data source designer, the data preview shows "Whoops! An error occurred" and Sintel BI shows:

There are more than 12 lookup columns visible, please reduce the number of visible lookup columns.

Widgets that use the data source may show "There is an issue with 1 or more data sources, contact your admin".

Cause

The list behind the data source has many lookup-type columns. SharePoint doesn't allow more than 12 lookup columns in one list view (the list view lookup threshold), and the same limit applies to a Sintel BI data source.

In SharePoint, all of these column types count as lookups:

1. Lookup columns
2. Managed metadata (single and multi-value)
3. Person or Group (single and multi-value)
4. Workflow status columns
5. Created By (a Person or Group column)
6. Modified By (a Person or Group column)

Fix

Who can fix this

Anyone who can edit the data source.

Hide lookup-type columns you don't need, until 12 or fewer are visible:

1. Open the data source in the data source designer.
2. Find the lookup-type columns. Hover over a column's type icon to see its type, for example Lookup - Single line of text, User or MultiUser.
3. Click the eye icon next to the columns you don't need to hide them.
4. Click Refresh in the data preview to check that data is returned, then save the data source.