SP 2013 - SharePoint List Not Filtering

I have a list that contains 5072 items.  When the list was created and as it's content grew - knowing it would exceed 5000 items, indexes and views were set up to return items.  Now none of the views return more than 5000 items.  Since the upgrade to 2016, there is a problem with filtering the views.  The selections either won't filter or return this error:

'Cannot show the value of the filter.  The filed may not be filterable, or the number of items returned exceeds the list view threshold enforced by the administrator'. 

I created a test view that returns a total of 351 items but that also can't be filtered by more than one value.  Has anyone else seen this issue?  If so please provide guidance and examples for correcting the issue.

Thanks!

Tom