Netsuite Sales import csv stopped working

Having an unusual situation.  First some background.  We have been using Netsuite in our current configuration for about 10 years now.  Our web site is not directly connected to Netsuite.  To bring orders in we do an export of customer and sales records made on the web site and import them via two csv files.  (Customer import then sales.)  Today, the sales records import stopped working for the most part.

Using the same saved import, we started getting this error after the Field Mapping step:

     One of the columns [id, externalid] must be mapped in the SALESORDER import

Nothing has changed in the file format or saved import.  However, what is very odd is I found one computer/browser it works and the rest in the office it did not.  (My computer actually.)  Of five PCs, four generated this error using the same account, mine as Administrator.  On the one that still works, it works if using Firefox but not Chrome.  One of the not working PCs is using the same version of Windows 10 and Firefox (72.0.2 64-bit) as the working one for comparison.  The non-working one has no enabled browser add-ons.  The working one has several. (Ad