Sharepoint data returned as NULL instead of a number in Tableau?

We have a SharePoint connection through Tableau and for some reason all the other data comes in fine but one column comes in as all NULL values when I know that data is a double with values in most of the fields.

Column of data in the SharePoint site shows values:

When reviewing the data in Tableau the values are all Null:

Another odd thing is that we cannot preview the data in Tableau data source tab.
The option to select the preview data is grayed out and I have never had this happen before.
Maybe its a issue with SharePoint data as I have never connected to SharePoint before with Tableau.

Unfortunately I cannot provide more data. It is confidential.

Has anyone run into this problem before?

So far all the research I have found has returned nothing useful.