I have a task list in SharePoint 2013. Tasks will be assigned to team members so a column 'Assigned To' was set up in 'people' format only. The view Filter was set as 'Show all items in this view'. However, This column is not able to be sortable or filterable in the view. I received error message: Cannot show the value of the filter. The field may not be filterable, or the number of items returned exceed the list view threshold enforced by the administrator. One thing I want to mention here is this column title is colored in light grey which is not same as other filterable columns which are in color light red.
Please advise how to make this column sortable and filterable?
Thanks,
Annie Tang


