The error message, "Failed to add data" is returned when adding a geodatabase table to a map in ArcGIS Pro.

Workaround

1. Select Query Layer from the Add Data drop-down on the ArcGIS Pro ribbon and select a geodatabase connection.
2. Drag the tables from the List of Tables section into the Query text box.
3. Click Validate, and click Next.
4. Right-click the query layer from the Contents pane, display it with a unique identifier and not a null field to display all records upon opening the attribute table.

Steps to Reproduce