Connecting to a SharePoint List Office 365 error

[3sun_Jack]

Hi I am receiving the following error when I try and link a SharePoint site to Power BI

DataSource.Error: We couldn't parse OData response result.  Error: A null value was found for the property named 'Actionee1Id', which has the expected type 'Collection(Edm.Int32)[Nullable=False]'. The expected type 'Collection(Edm.Int32)[Nullable=False]' does not allow null values.
Details:
    DataSourceKind=SharePoint
    DataSourcePath=https://#######.sharepoint.com/BD/_api/Web/Lists(guid'#####-####-###-###-#####')/Items

I have seen this error before, but previously I could delete the column in question, unfortunately, this time I cannot

the field in question is a people field which is non mandatory

any help would be gratefully received

Kindest regards

Jack